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Controlled modulation of the spin-crossover (SCO) behavior through the sorption-desorption of invited molecules is an extensively exploited topic because of its potential applications in molecular sensing. For this purpose, understanding the mechanisms by which the spin-switching properties are altered by guest molecules is of paramount importance. Here, we show an experimental approach revealing a direct probe of how the interplay between SCO and host-guest chemistry is noticeably activated by chemically tuning the host structure. Thus, the axial ligand 4-phenylpyridine (4-PhPy) in the 2D Hofmann clathrates {Fe(4-PhPy)2[M(CN)4]} (PhPyM; M = Pt, Pd) is replaced by 2,4-bipyridine (2,4-Bipy), resulting in the isomorphous compounds {Fe(2,4-Bipy)2[M(CN)4]} (BipyM; M = Pt, Pd), which basically differ from the former in that they have a noncoordinated N heteroatom in the ancillary aromatic substituent, i.e., 2-pyridyl instead of phenyl. Our chemical, magnetic, calorimetric, and structural characterizations demonstrate that this subtle chemical composition change provokes outstanding modifications not only in the capability to adsorb small guests as water or methanol but also in the extent to which these guests affect the SCO characteristics.

Self-assembly of [Hg(SeCN)4]2- tetrahedral building blocks, iron(II) ions, and a series of bis-monodentate pyridyl-type bridging ligands has afforded the new heterobimetallic HgII-FeII coordination polymers {Fe[Hg(SeCN)3]2(4,4'-bipy)2}n (1), {Fe[Hg(SeCN)4](tvp)}n (2), {Fe[Hg(SeCN)3]2(4,4'-azpy)2}n (3), {Fe[Hg(SeCN)4](4,4'-azpy)(MeOH)}n (4), {Fe[Hg(SeCN)4](3,3'-bipy)}n (5) and {Fe[Hg(SeCN)4](3,3'-azpy)}n (6) (4,4-bipy = 4,4'-bipyridine, tvp = trans-1,2-bis(4-pyridyl)ethylene, 4,4'-azpy = 4,4'-azobispyridine, 3,3-bipy = 3,3'-bipyridine, 3,3'-azpy = 3,3'-azobispyridine). Single-crystal X-ray analyses show that compounds 1 and 3 display a two-dimensional robust sheet structure made up of infinite linear [(FeL)n]2n+ (L = 4,4'-bipy or 4,4'-azpy) chains linked by in situ formed {[Hg(L)(SeCN)3]2}2- anionic dimeric bridges. Complexes 2 and 4-6 define three-dimensional networks with different topological structures, indicating, in combination with complexes 1 and 3, that the polarity, length, rigidity, and conformation of the bridging organic ligand play important roles in the structural nature of the products reported here. The magnetic properties of complexes 1 and 2 show the occurrence of temperature- and light-induced spin crossover (SCO) properties, while complexes 4-6 are in the high-spin state at all temperatures. The current results provide a new route for the design and synthesis of new SCO functional materials with non-Hofmann-type traditional structures.

The research of new multifunctional materials, as those undergoing spin crossover (SCO) and luminescent properties, is extremely important in the development of further optical and electronic switching devices. As a new step towards this ambitious aim, the coupling of SCO and fluorescence is presented here following two main strategies: whether the fluorescent agent is integrated as a part of the main structure of a 3D SCO coordination polymer {FeII(bpan)[MI(CN)2]2} (bpan = bis(4-pyridyl)anthracene, MI = Ag (FebpanAg), Au (FebpanAu)) or is a guest molecule inserted within the cavities of the 3D switchable framework {FeII(bpb)[MI(CN)2]2}·pyrene (bpb = bis(4-pyridyl)butadiyne, MI = Ag (FebpbAg·Pyr), Au (FebpbAu·Pyr)). The magnetic, calorimetric, structural, UV-Vis absorption and fluorescent characterizations were performed confirming the occurrence of a SCO-fluorescence interplay in the studied compounds. Moreover, the relevance of the intrinsic or extrinsic nature of the luminescence on the efficiency of the interplay is discussed on the basis of the available information.

The enantioselective 1,4-alkynylation of conjugated imines derived from saccharin with aryl- and alkyl-substituted terminal alkynes has been achieved. The reaction mediated by diethylzinc in the presence of a catalytic amount of a bis(hydroxy)malonamide chiral ligand provides the corresponding imines bearing a propargylic stereocenter with moderate yields and fair to excellent enantioselectivities.

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Rare loop-like isostructural one-dimensional coordination polymer (1D-CP) systems formulated as {Fe(DPIP)2(NCSe)2}n·4DMF (1) and {Fe(DPIP)2(NCSe)2}n·4DMF (2) were obtained by self-assembling FeII and pseudohalide NCX−(X = S, Se) ions in presence of the V-shaped bidentate bridging ligand, namely, N,N′-dipyridin-4-ylisophthalamide (DPIP), and were characterized by elemental analysis, IR spectroscopy, TGA, single crystal X-ray diffraction and powder X-ray diffraction. The magnetic studies show that complex 2 undergoes a complete thermally induced spin crossover (SCO) behavior centered at T1/2 = 120 K with ca. 5 K thermal hysteresis loop and light-induced excited spin state trapping effect (LIESST) with TLIESST = 65 K. However, either the homologous X = S (1) or the desolvated form of complex 2 is high spin at all temperatures, proving further the concerted synergy for the SCO of 2 between the intrinsic ligand field and that indirectly induced via hydrogen bond interaction. The current results provide valuable information for the design of new 1D SCO systems via the rational control of the cooperated effects derived from the intramolecular coordination bond and the intermolecular supramolecular interactions.

Herein, an efficient asymmetric aminoalkylation of pyrazolones with α-amido sulfones catalyzed by a quinine-derived squaramide in dichloromethane/aqueous media has been established. A variety of chiral amines were obtained with high yields (up to 98%) and excellent enantioselectivities (up to 99% ee). The corresponding products are transformed into optically active acetylated pyrazoles after treatment with Ac2O/Et3N, because of the instability of some adducts. The reaction tolerates a wide range of α-amido sulfones and different pyrazolones.

[EN] Self-assembly of octahedral FeII ions, trans-1,2-bis(4-pyridyl) ethane (bpe) bridging ligands and [Hg(XCN)(4)](2-) (X = S (1), Se (2)) tetrahedral building blocks has afforded a new type of hetero-bimetallic Hg-II-Fe-II spin-crossover (SCO) 3D 6,4-connected coordination polymer (CP) formulated {Fe(bpe)[Hg(XCN)(4)]}(n). For X = S (1), the ligand field is close to the crossing point but 1 remains paramagnetic over all temperatures. In contrast, for X = Se (2) the complex undergoes complete thermal induced SCO behaviour centred at T-1/2 = 107.8 K and complete photoconversion of the low spin state into a metastable high-spin state (LIESST effect) with T-LIESST = 66.7 K. The current results provide a new route for the design and synthesis of new SCO functional materials with non-Hoffmann-type structures., We are very thankful for the support from the National Natural Science Foundation of China (21671121 and 21773006) the Spanish Ministerio de Economiay Competitividad (MINECO) and FEDER funds (CTQ2016-78341-P and Unidad de Excelencia Maria de Maeztu MDM-2015-0538), and Generalitat Valenciana (PROMETEO/2016/147). F. J. V. M. thanks MINECO for a predoctoral FPI grant.

A binary reversible switch between low-temperature multi-step spin crossover (SCO), through the evolution of the population γHS(T) with high-spin (HS)-low-spin (LS) sequence: HS1LS0 (state 1) ↔ HS2/3LS1/3 (state 2) ↔ HS1/2LS1/2 (state 3) ↔ HS1/3LS2/3 (state 4) ↔ HS0LS1 (state 5), and complete one step hysteretic spin transition featuring 20 K wide thermal hysteresis centred at 290 K occurs in the three-dimensional (3D) Hofmann-type porous coordination polymer {FeII(3,8phen)[Au(CN)2]2}·xPhNO2 (3,8phen = 3,8-phenanthroline, PhNO2 = nitrobenzene), made up of two identical interpenetrated pcu-type frameworks. The included PhNO2 guest (x = 1, 1·PhNO2) acts as a molecular wedge between the interpenetrated 3D frameworks via PhNO2-3,8phen intermolecular recognition and is the source of the strong elastic frustration responsible for the multi-step regime. Detailed X-ray single crystal analysis reflects competition between spatial periodicities of structurally inequivalent HS and LS SCO centres featuring: (i) symmetry breaking (state 3) with ⋯HS–LS⋯ ordering with γHS = 1/2; and (ii) occurrence of spatial modulation of the structure providing evidence for stabilization of local or aperiodic ordered mixed spin states for states 2 and 4 (with γHS ≈ 2/3) and 4 (with γHS ≈ 1/3), respectively. Below c.a. 20 K, structural and magnetic analyses show the photogeneration of a metastable HS*, state 6. The room-temperature single-step hysteretic regime appears with release of the guest (x = 0, 1) and the elastic frustration, and reversibly switches back to the original four-step behaviour upon guest re-adsorption. Both uncommon relevant SCO events meeting in the same material represent a rare opportunity to compare them in the frame of antiferro- and ferro-elastic transitions., Reversible switch between a robust bistable two-state room temperature spin crossover (SCO) and its transformation in a four-stepped elastically frustrated SCO due to guest inclusion in a metal–organic Hofmann framework.

A valuable organocatalytic vinylogous Mannich reaction between alkylidenepyrazolones and isatin-derived ketimines has been successfully established. Squaramide organocatalyst, prepared from quinine, catalyzed the diastereo- and enantioselective vinylogous Mannich addition, affording a range of aminooxindole-pyrazolone adducts (24 examples) with excellent outcomes: up to 98% yield with complete diastereoselectivity and excellent enantioselectivity (up to 99% ee). Additionally, different synthetic transformations were performed with the chiral pyrazolone-oxindole adducts.

An enantioselective organocatalytic addition of sodium bisulfite to (E)-nitroalkenes has been developed by using a chiral bifunctional organocatalyst. The present methodology provides a variety of chiral β-nitroethanesulfonic acid compounds (17 examples) with excellent results: up to 99% yield and excellent enantioselectivity (up to 96% ee). The reaction tolerates (hetero)aryl and alkyl substituents on the β-nitroalkenes, and β,β-disubstituted nitroalkenes.

[EN] An asymmetric catalytic reaction of hydroxyindoles with nitroalkenes leading to the Friedel-Crafts alkylation in the carbocyclic ring of indole is presented. The method is based on the activating/directing effects of the hydroxy group situated in the carbocyclic ring of the indole providing nitroalkylated indoles functionalizated at the C-4, C-5, and C-7 positions with high yield, regio-, and enantioselectivity. The optically enriched nitroalkanes were transformed efficiently in optically enriched 2-amino-1,1-diarylalkanes bearing a carbocyclic ring substituted indole., Financial support from the MINECO (Gobierno de Espana; CTQ2017-84900-P) is gratefully acknowledged. C.V. thanks MINECO for a JdC contract. J.R.-B. thanks the Ministry of Education for a Collaboration grant. Access to NMR, MS, and X-ray facilities from the Servei Central de Suport a la Investigacio Experimental (SCSIE)-UV is also acknowledged

[EN] The search for bifunctional materials showing synergies between spin crossover (SCO) and luminescence has attracted substantial interest since they could be promising platforms for new switching electronic and optical technologies. In this context, we present the first three-dimensional Fe-II Hofmann-type coordination polymer exhibiting SCO properties and luminescence. The complex {Fe-II(bpben)[Au(CN)(2)]}@pyr (bpben = 1,4-bis(4-pyridyl)benzene) functionalized with pyrene (pyr) guests undergoes a cooperative multi-step SCO, which has been investigated by single crystal X-ray diffraction, single crystal UV-Vis absorption spectroscopy, and magnetic and calorimetric measurements. The resulting fluorescence from pyrene and exciplex emissions are controlled by the thermal and light irradiation (LIESST effect) dependence of the high/low-spin state population of Fe-II. Conversely, the SCO can be tracked by monitoring the fluorescence emission. This ON-OFF interplay between SCO and luminescence combined with the amenability of Hofmann-type materials to be processed at the nano-scale may be relevant for the generation of SCO-based sensors, actuators and spintronic devices., This work was supported by the Spanish Ministerio de Economia y Competitividad (MINECO), FEDER (CTQ2013-46275-P and CTQ2016-78341-P), Unidad de Excelencia Maria de Maeztu (MDM-2015-0538), Generalitat Valenciana (PROMETEO/2016/147) and the Swiss National Science Foundation (Project number 200021-169033).

[EN] A highly enantioselective addition of hydroxyquinolines to isatin-derived ketimines has been realized using a quinine-derived thiourea organocatalyst. The reaction affords chiral 3-amino-2-oxindoles bearing a quinoline moiety with a quaternary stereocenter in high yields (up to 98%) and excellent enantioselectivities (up to 99%). Moreover, we can extend this methodology for the enantioselective functionalization of 5-hydroxyisoquinoline. This methodology represents, to the best of our knowledge, the first enantioselective addition of hydroxyquinolines to imines., Financial support from the MINECO (Gobierno de Espana; CTQ2013-47494-P) is gratefully acknowledged. C.V. thanks MINECO for a JdC contract and M.M-M. thanks Universitat de Valencia for a pre-doctoral grant.

[EN] Competition between spin-crossover and structural ligand ordering is identified as responsible for multistability and generation of six different phases in a rigid two-dimensional coordination polymer formulated {Fe-II[Hg-II(SCN)(3)](2) mu-(4,4'-bipy)(2)}(n) (1) (4,4'-bipy = 4,4'-bipyridine). The structure of 1 consists of infinite linear [Fe(mu-4,4'-bipy)](n)(2n+) chains linked by in situ formed {[Hg-II(SCN)(3)](2)(mu-4,4'-bipy)}(2n-) anionic dimers. The thermal dependence of the high-spin fraction, his, features four magnetic phases defined by steps following the sequence gamma(HS) = 1 (phase 1) gamma(HS) = 1/2 (phase 2) gamma(HS) approximate to 1/3 (phase 3) gamma(HS) = 0 (phase 4) These four magnetic states are consistent with structural ordering stemming from the different commensurate or incommensurate high and low-spin populations [HS] [HS:LS], approximate to [HS:2LS] [LS1] inferred from single crystal-analysis. Furthermore, two additional phases are generated at low temperature. One, LS2 (gamma(HS) = 0, phase 5); is due to spontaneous symmetry breaking of the : LS-1 state below 85 K The other results from irradiating the low-temperature-LS2 Phase at 15 K with red light to photogenerate a HS phase of low symmetry (HS*) (gamma(HS) = 1, phase 6). Detailed structural studies of the six phases-unravd the pivotal role-played by the internal dihedral angle of the 4,4'-bipy ligands in the microscopic. mechanism responsible for multistability and multistep behavior in 1., This work was supported by the Spanish Ministerio de Economia y Competitividad (MINECO), FEDER (CTQ2013-46275-P and CTQ2016-78341-P), Unidad de Excelencia Maria de Maeztu (MDM-201S-0538), the Generalitat Valenciana through PROMETEO/2016/147, and the Institut Universitaire de France, the National Research Agency (ANR-13-BS04-0002), Rennes Metropole and CNRS (Post-Doc funding of E.T.). L.P.L. and F.J.V.M. thank to the Universidad de Valencia and a MINECO for a predoctoral (FPI) grant. Prof. D. Zhang thanks for the support from the Natural Science Foundation of China (21671121).

[EN] Copper triflate-BOX complexes catalyse the enantioselective conjugate addition of methyl malonate to beta-trifluoromethyl-alpha,beta-unsaturated imines to give the corresponding enamines bearing a trifluoromethylated stereogenic centre with good yields, and diastereo- and enantioselectivities. The usefulness of the method has been shown with the synthesis of optically active beta-trifluoromethyl delta-amino esters and optically active trifluoromethyl piperidones., Financial support (CTQ2013-47494-P) from the Ministerio de Economia y Competitividad (MINECO-Gobierno de Espana). M. E. acknowledges the Generalitat Valenciana for a predoctoral grant. Access to NMR and MS facilities from the Servei Central de Suport a la Investigacio Experimental (SCSIE)-UV is also acknowledged.

A catalytic highly enantioselective aza-Reformatsky reaction with cyclic aldimines and ketimines for the synthesis of chiral b-amino esters with good yields and excellent enantioselectivities is reported.Areadily available diaryl prolinol is used as a chiral ligand, ZnMe2 as a zinc source and ethyl iodoacetate as reagent in the presence of air atmosphere. The reaction with cyclic ketimines generates a quaternary stereocenter with excellent levels of enantioselectivity. Furthermore, five-membered N-sulfonyl ketimines were used as electrophiles with good enantiomeric excesses, under the optimized reaction conditions. Moreover, several chemical transformations were performed with the chiral b-amino esters., Financial support from the MINECO (Gobierno de Espana; CTQ2013-47494-P). L.D.M. thanks the Generalitat Valenciana for a predoctoral grant. C.V. thanks MINECO for a JdC contract. Access to NMR, MS and X-ray facilities from the Servei central de suport a la investigacio experimental (SCSIE)-UV is also acknowledged.

[EN] An enantioselective photooxidative Mannich reaction of dihydroquinoxalinones with ketones by the merger of organophotoredox and asymmetric organocatalysis is described. This protocol features very mild reaction conditions using simple and cheap catalysts (Eosin Y and (S)-Proline) for the synthesis of chiral quinoxaline derivatives with good to high yields (up to 94%) and excellent enantioselectivities (up to 99% ee)., Financial support from the Agencia Estatal de Investigation (AEI, Spanish Government) and Fondo Europeo de Desarrollo Regional (FEDER, European Union) (CTQ2017-84900-P) is acknowledged. J.R.-B. thanks the Ministerio de Ciencia, Innovacion y Universidades for an FPU predoctoral contract, and C.V. thanks the Agencia Estatal de Investigacion (AEI, Spanish Government) for an RyC contract (RYC-2016-20187).

[EN] A multistable spin crossover (SCO) molecular alloy system [Fe1-xMx(nBu-im)(3)(tren)](P1-yAsyF6)(2) (M = Zn-II, Ni-II; (nBu-im)(3)(tren) = tris(n-butyl-imidazol(2-ethylamino))amine) has been synthesized and characterized. By controlling the composition of this isomorphous series, two cooperative thermally induced SCO events featuring distinct critical temperatures (T-c) and hysteresis widths (Delta T-c, memory) can be selected at will. The pristine derivative 100As (x = 0, y = 1) displays a strong cooperative two-step SCO and two reversible structural phase transitions (PTs). The low temperature PTLT and the SCO occur synchronously involving conformational changes of the ligand's n-butyl arms and two different arrangements of the AsF6- anions [T-c(1) = 174 K (Delta T-c(1) = 17 K), T-c(2) = 191 K (Delta T-c(2) = 23 K) (scan rate 2 K min(-1))]. The high-temperature PTHT takes place in the high-spin state domain and essentially involves rearrangement of the AsF6- anions [T-c(PT) = 275 K (Delta T-c(PT) = 16 K)]. This behavior strongly contrasts with that of the homologous 100P [x = 0, y = 0] derivative where two separate cooperative one-step SCO can be selected by controlling the kinetics of the coupled PTLT at ambient pressure: (i) one at low temperatures, T-c = 122 K (Delta T-c = 9 K), for temperature scan rates (>1 K min(-1)) (memory channel A) where the structural modifications associated with PTLS are inhibited; (ii) the other centered at T-c = 155 K (Delta T-c = 41 K) for slower temperature scan rates PF6- substitution, and hence of the PTLT kinetics, selectively selects the memory channel B of 100P when x = 0 and y approximate to 0.7. Meanwhile, substitution of Fe-II with Zn-II or Ni-II [x approximate to 0.2, y = 0] favors the low temperature memory channel A at any scan rate. This intriguing interplay between PT, SCO and isomorphous substitution was monitored by single crystal and powder X-ray diffractometries, and magnetic and calorimetric measurements., This work was supported by the Spanish Ministerio de Economia y Competitividad (MINECO), FEDER (CTQ2016-78341-P), Unidad de Excelencia Maria de Maeztu (MDM-2015-0538), and the Generalitat Valenciana through PROMETEO/2016/147 and an EU Framework Program for Research and Innovation (RISE project number 734322). F. J. V. M. and M. M. S. thank MINECO for a predoctoral (FPI) grant.

[EN] An organocatalytic enantioselective functionalization in the carbocyclic ring of indoles with benzoxathiazine 2,2-dioxides is described using a quinine-derived bifunctional organocatalyst. This aza-Friedel-Crafts reaction provides 4-indolyl, 5-indolyl and 7-indolyl sulfamidate derivatives in good yields (up to 99%) and with moderate to high enantioselectivities (up to 86% ee)., Financial support from the Agencia Estatal de Investigación (AEI, Spanish Government) and Fondo Europeo de Desarrollo Regional (FEDER, European Union) (CTQ2017-84900-P) is acknowledged. C. V. thanks the Spanish Government for the RyC contract (RYC-2016-20187).

[EN] The synthesis, structural characterization and magnetic properties of two new isostructural porous 3D compounds with the general formula {FeII(pina)[MI(CN)2]2}·xMeOH (x = 0¿5; pina = N-(pyridin-4-yl)isonicotinamide; MI = AgI and x ~ 5 (1·xMeOH); MI = AuI and x ~ 5 (2·xMeOH)) are presented. The single-crystal X-ray diffraction analyses have revealed that the structure of 1·xMeOH (or 2·xMeOH) presents two equivalent doubly interpenetrated 3D frameworks stabilized by both argentophilic (or aurophilic) interactions and interligand C¿O···HC H-bonds. Despite the interpenetration of the networks, these compounds display accessible void volume capable of hosting up to five molecules of methanol which interact with the host pina ligand and establish an infinite lattice of hydrogen bonds along the structural channels. Interestingly, the magnetic studies have shown that solvated complexes 1·xMeOH and 2·xMeOH display two- and four-step hysteretic thermally driven spin transitions, respectively. However, when these compounds lose the methanol molecules, the magnetic behavior changes drastically giving place to gradual spin conversions evidencing the relevant influence of the guest molecules on the spin-crossover properties. Importantly, since the solvent desorption takes place following a single-crystal-to-single-crystal transformation, empty structures 1 and 2 (x = 0) could be also determined allowing us to evaluate the correlation between the structural changes and the modification of the magnetic properties triggered by the loss of methanol molecules., We thank the Spanish Ministerio de Economia y Competitividad (MINECO), FEDER funds (CTQ2016-78341-P and Unidad de Excelencia Maria de Maeztu MDM-2015-0538), and Generalitat Valenciana (PROMETEO/2016/147). F.J.V.-M. thanks MINECO for a predoctoral FPI grant.

[EN] The first enantioselective formal [3 + 2] cycloaddition between ¿-isocyanoesters and trifluoromethylketones to give 5-trifluoromethyl-2-oxazolines bearing two contiguous stereogenic centers, one of them being a quaternary stereocenter substituted with a CF3 group, has been developed. The reaction is based upon a multicatalytic approach that combines a bifunctional Brønsted base-squaramide organocatalyst and Ag+ as Lewis acid. The reaction could be achieved with a range of aryl and heteroaryl trifluoromethyl ketones, and the resulting oxazolines were obtained with good to excellent diastereo- and enantioselectivity., Financial support from the MINECO and FEDER (CTQ2017-84900-P). Access to NMR and MS facilities from SCSIE-UV. C.V. thanks the Spanish Government for a Ramon y Cajal contract (RyC-2016-20187). A.S.-M. thanks the Generalitat Valenciana and Fondo Social Europeo for a postdoctoral grant (APOST/2016/139).

In congenital hydrocephalus, cerebrospinal fluid accumulation is associated with increased intracranial pressure (ICP), ischemia/hypoxia, metabolic impairment, neuronal damage, and astrocytic reaction. The aim of this study was to identify whether a metabolite profile revealing tissue responses according to the severity of hydrocephalus can be detected. The hyh mutant mouse used for this study exhibits 2 different forms of hydrocephalus, severe and moderate. In a comprehensive investigation into the 2 progressions of hydrocephalus, mice with severe hydrocephalus were found to have higher ICP and astrocytic reaction. Several metabolites from the mouse brain cortex were analyzed with 1H high-resolution magic angle spinning nuclear magnetic resonance (1H HR-MAS NMR) spectroscopy. A differential profile for metabolites including glutamate and glutamine was found to correlate with the severity of hydrocephalus and can be explained due to differential astrocytic reactions, neurodegenerative conditions, and the presence of ischemia. The glutamate transporter EAAT2 and the metabolite taurine were found to be key histopathological markers of affected parenchymata. In conclusion, a differential metabolite profile can be detected according to the severity of hydrocephalus and associated ICP and therefore can be used to monitor the efficacy of experimental therapies.

[EN] Fe-II spin-crossover (SCO) coordination polymers of the Hofmann type have become an archetypal class of responsive materials. Almost invariably, the construction of their architectures has been based on the use of monotopic and linear ditopic pyridine like ligands. In the search for new Hofmann-type architectures with SCO properties, here we analyze the possibilities of bridging ligands with higher connectivity degree. More precisely, the synthesis and structure of {Fe-II(L-N3)[M-I(CN)(2)](2)}center dot(Guest) (Guest = nitro-benzene, benzonitrile, o-dichlorobenzene; M-I = Ag, Au) and {Fe-II(L-N4)[Ag-2(CN)(3)][Ag(CN)(2)]}center dot H2O are described, where L-N3 and L-N4 are the tritopic and tetratopic ligands 1,3,5-tris(pyridin-4-ylethynyl)benzene and 1,2,4,5-tetrakis(pyridin-4-ylethynyl)benzene. This new series of Hofmann clathrates displays thermo- and photoinduced SCO behaviors., We thank the Spanish Ministerio de Economia y Competitividad (MINECO) and FEDER funds (CTQ2013-46275-P and CTQ2016-78341-P and Unidad de Excelencia Maria de Maeztu MDM-2015-0538), and Generalitat Valenciana (PROMETEO/2016/147). FJ.V.-M. thanks MINECO for a predoctoral FPI grant. We also thank Dr. Carlos Marti for helping us with ToposPro software.

The highly stable nitrosyl iron(II) mononuclear complex [Fe(bztpen)(NO)](PF6)(2) (bztpen=N-benzyl-N,N',N'-tris(2-pyridylmethyl)ethylenediamine) displays an S=1/2 S=3/2 spin crossover (SCO) behavior (T-1/2=370 K, Delta H= 12.48 kJmol(-1), Delta S=33 JK(-1) mol(-1)) stemming from strong magnetic coupling between the NO radical (S=1/2) and thermally interconverted (S=0 S=2) ferrous spin states. The crystal structure of this robust complex has been investigated in the temperature range 120-420 K affording a detailed picture of how the electronic distribution of the t(2g)-e(g) orbitals modulates the structure of the {FeNO}(7) bond, providing valuable magneto-structural and spectroscopic correlations and DFT analysis., The research reported here was supported by the Spanish Ministerio de Economia y Competitividad (MINECO) and FEDER funds (CTQ2013-46275-P, CTQ2015-64579-C3-1-P, and Unidad de Excelencia Maria de Maeztu MDM-2015-0538) and the Generalitat Valenciana (PROMETEO/2012/049). L.P.L. thanks the Generalitat Valenciana and the Universidad de Valencia for a predoctoral fellowship. J.C. and E.R. thank the Generalitat de Catalunya for a Beatriu de Pinos grant and an ICREA Academia award, respectively.

[EN] The unprecedented bimetallic 2D coordination polymer {Fe[(Hg(SCN)3)2](4,4’-bipy)2}n exhibits a thermal high-spin (HS)$low-spin (LS) staircase-like conversion characterized by a multi-step dependence of the HS molar fraction gHS. Between the fully HS (gHS = 1) and LS (gHS = 0) phases, two steps associated with different ordering appear in terms of spin-state concentration waves (SSCW). On the gHS 0.5 step, a periodic SSCW forms with a HS-LS-HS-LS sequence. On the gHS 0.34 step, the 4D superspace crystallography structural refinement reveals an aperiodic SSCW, with a HS-LS sequence incommensurate with the molecular lattice. The formation of these different long-range spatially ordered structures of LS and HS states during the multi-step spin-crossover is discussed within the framework of “DevilÏs staircase”-type transitions. Spatially modulated phases are known in various types of materials but are uniquely related to molecular HS/LS bistability in this case., This work was supported by the Spanish Ministerio de Economia y Competitividad (MINECO), FEDER (CTQ2013-46275-P), Unidad de Excelencia Maria de Maeztu MDM-2015-0538, the Generalitat Valenciana through PROMETEO/2012/049. L.P.L. and F.J.V.M. thank the Universidad de Valencia and a MINECO for a predoctoral (FPI) grant. D.Z. thanks the Natural Science Foundation of China and China Scholarship Council. This work was supported by the Institut Universitaire de France, the National Research Agency (ANR-13-BS04-0002), Rennes Metropole and CNRS (Post-Doc funding of E.T.). E.C. and J.A.R. would like to thank G. Chastanet for meditations on the Devil's staircase.

A quinine-derived thiourea catalysed the enantioselective addition of 4-substituted pyrazolones to isatin-derived ketimines, providing a variety of aminooxindole-pyrazolone adducts containing congested vicinal tetrasubstituted stereocentres with excellent outcomes (up to 98% yield, >20:1 dr and 98% ee)., Financial support from the MINECO (Gobierno de Espana and FEDER (EU)) (CTQ2013-47949-P) and from Generalitat Valenciana (ISIC2012/001) is gratefully acknowledged. C. V. thanks MINECO for JdC contract. Access to NMR, MS and X-ray facilities from the Servei central de support a la investigacio experimental (SCSIE)-UV is also acknowledged.

A new octacoordinated Fe(II) compound, [FeII(LN4)2](BPh4)2·3CH2Cl2, as an example of the scarce FeN8 systems, has been isolated with a tetradentate triazolopyridine-based ligand from a solution containing the related hexacoordinated [FeII(LN3)2]2+ complex, with LN3 = pyridyltriazolo-pyridyl-bromopyrimidine and LN4 = bis(pyridyltriazolo-pyridine)., This work was financially supported by the Ministerio de Ciencia e Innovacion (Spain) (Project CONSOLIDER-INGENIO SUPRAMED CSD 2010-00065), Ministerio de Economia y Competitividad (MINECO), FEDER funds (Project CTQ2013-46275-P), Unidad de Excelencia Maria de Maeztu (MdM-2015-0538), and Generalitat Valenciana (Project PROMETEO/2016/147). R. B.-G. is very much indebted to the Postdoctoral fellowship of the Ministerio de Economia y Competitividad (Spain).

A series of spin transition neutral compounds [FeL(NCS)2] has been synthesized and characterized by means of magnetic susceptibility studies, X-ray diffraction, IR and Mossbauer spectroscopic, and calorimetric measurements (L = N,N-bis((3-alkoxypyridin-2-yl)methylene)-propane-1,3-diamine, number of carbon atoms in chains (n) = 4, 12, 14, 16, 18, 20). The shortest chain compound is crystalline and displays a gradual spin transition above ambient temperature. Growing the aliphatic substituent up to n = 12 and 14 leads to loss of crystalline order and deterioration of magnetic properties. At the critical chain length n = 16 and above, the compounds undergo a phase transition reflected by a spin transition and resulting in the appearance of susceptibility hysteresis initially not observed for the short chain congener. For the compound with n = 20, hysteresis becomes the most pronounced. The study shows the importance of chain length optimization for effective feedback between phase and spin transitions.

A new enantioselective route to spiro[piperidine-3,3′-oxindoles] from isatin ketimines is described. The aza-Henry reaction of N-Boc-isatin ketimines with methyl 4-nitrobutyrate in the presence of a Ph2BOX-CuBr2 complex provided the corresponding nitro amino esters with good diastereoselectivity and excellent enantioselectivity (up to >99% ee). The aza-Henry adducts were transformed into spiro[piperidine-3,3′-oxindoles] after reduction of the nitro group to oxime, and cleavage of the N-Boc group and lactamisation.

[EN] We report an unprecedented series of two-dimensional (2D) spin-crossover (SCO) heterobimetallic coordination polymers generically formulated as {Fe-II[(He(SCN)(3))(2)](L)(x))}center dot Solv, where x = 2 for L = tvp (trans-(4,4'-vinylenedipyridine)) (1tvp), bpmh ((1E,2E)-1,2-bis(pyridin-4-ylmethylene)hydrazine) (1bpmh center dot nCH(3)OH; n = 0, 1), by eh ( (1E,2E)-1,2-bis (1-(pyridin-4-yl) ethyliden e) hydrazine) (Ibpeh center dot nH(2)O; n = 0, 1) and x = 2.33 for L = 0 0 bpbz (1,4-bis(pyridin-4-yl)benzene) (1bpbz center dot nH(2)O; n = 0, 2/ 3). The results confirm that self-assembly of Fell, [Hg-II(SCN)(4)](2-), and ditopic rodlike bridging ligands L containing 4-pyridyl moieties favors the formation of linear [Fe(mu-L)](n)(2n+) chains and in situ generated binuclear units {[Hg-II(SCN)(3)](2)(mu-L)}(2)-. The latter act as bridges between adjacent chains generating robust 2D layers. The [(FeN6)-N-II] centers are equatorially surrounded by four NCS- groups and two axial N atoms of the organic ligand L. The compound 1tvp and the unsolvated form of 1bpmh undergo complete SCO centered at T-1/2 = 177 and 226 K, characterized by the enthalpy and entropy variations Delta H = 12.3 and 10.5 kJ mol(-1) and Delta S = 69.4 and 48 J KT-1 mol(-1), respectively. The almost complete SCO of the unsolvated form of 1bpeh occurs at ca. T-1/2 = 119 K and exhibits a complete LIESST effect. Regardless of the degree of solvation, a half-spin conversion at T-1/2 < 100 K occurs for 1bpbz center dot nH(2)O, which becomes almost complete at p = 0.65 GPa. The labile solvent molecules present in 1bpmh center dot CH3OH and 1bpely center dot H2O have a dramatic influence on the corresponding SCO behavior., We thank the Spanish Ministerio de Economia y Competitividad (MINECO), FEDER funds (CTQ2013-46275-P and CTQ2016-78341-P and Unidad de Excelencia Maria de Maeztu MDM-2015-0538), and Generalitat Valenciana (PROMETEO/2016/147). FJ.V.-M. thanks MINECO for a predoctoral FPI grant. D.Z. acknowledges support from the Natural Science Foundation of China (21671121).

[EN] Two new 3D spin-crossover (SCO) Hofmann-type coordination polymers {Fe(2,6-naphthy)[Ag(CN)2][Ag2(CN)3]} (1; 2,6-naphthy = 2,6-naphthyridine) and {Fe(2,6-naphthy)- [Au(CN)2]2}·0.5PhNO2 (2) were synthesized and characterized. Both derivatives are made up of infinite stacks of {Fe[Ag(CN)2]2- [Ag2(CN)3]}n and {Fe[Au(CN)2]2}n layered grids connected by pillars of 2,6-naphthy ligands coordinated to the axial positions of the FeII centers of alternate layers., This work was supported by the Spanish Ministerio de Economia y Competitividad (MINECO), Fondos Europeos para el Desarrollo Regional (FEDER) (CTQ2013-46275-P and CTQ2016-78341-P), Unidad de Excelencia Maria de Maeztu (MDM-2015-0538), and the Generalitat Valenciana through PROMETEO/2016/147. L. P. L. and F. J. V. M. thank the Universidad de Valencia and MINECO, respectively for predoctoral (FPI) grants.

[EN] In this paper, we report the application of chiral complexes of La(III) with pyBOX ligands as Lewis acid catalysts in the conjugate addition of malonic esters to N-tosyl imines derived from ß,gamma-unsaturated alfa-keto esters to give the corresponding chiral alfa,ß-dehydroamino esters. pyBOX complexes with La(III), Yb(III), Sc(III), and In(III) triflates were assessed in this reaction but only La(III) showed good activity and enantioselectivity, while Yb(III) provided the expected product with low yield and stereoselectivity, and the Sc(III) and In(III) complexes were completely inactive. The complex of La(OTf)3 with the diphenyl-pyBOX ligand prepared in situ provided the best results and allowed obtaining chiral ¿,ß-dehydroamino esters 3 with excellent yields, E:Z diastereomeric ratios (29:71-99:1) and high enantiomeric excesses (20-95%). The reaction could be applied to imines having a substituted aromatic ring or a heterocycle attached to the double bond, although the presence of electron-withdrawing groups on the aromatic ring was detrimental for stereoselectivity. The reaction products were obtained with the S configuration at the stereogenic center and the Z configuration at the enamine double bond as determined by NOESY experiments and X-ray analysis. Based on the experimental results a stereochemical model involving a nine-coordinate La(III) species has been proposed., This work was supported by the Ministerio de Economia y Competitividad (MINECO-Gobierno de Espana) [grant number CTQ2013-47494-P].

[EN] A multicatalytic approach that combines a bifunctional Brønsted base¿squaramide organocatalyst and Ag+ as Lewis acid has been applied in the reaction of unactivated ketones with tert-butyl isocyanoacetate to give chiral oxazolines bearing a quaternary stereocenter. The formal [3+2] cycloaddition provided high yields of the corresponding cis-oxazolines with good diastereoselectivity and excellent enantioselectivity, being applied to aryl¿alkyl and alkyl¿alkyl ketones., Financial support from the Ministerio de Economia, Industria y Competitividad (Gobierno de Espana) and FEDER (European Union) (CTQ2017-84900-P) is acknowledged. C. V. thanks the Spanish Government for a Ramon y Cajal contract (RyC-2016-20187). A. S.-M. thanks the Generalitat Valenciana and Fondo Social Europeo for a post-doctoral grant (APOST/2016/139).

[Fe(tvp)(2)(NCS)(2)] (1) (tvp=trans-(4,4-vinylenedipyridine)) consists of two independent perpendicular stacks of mutually interpenetrated two-dimensional grids. This uncommon supramolecular conformation defines square-sectional nanochannels (diagonal approximate to 2.2nm) in which inclusion molecules are located. The guest-loaded framework 1@guest displays complete thermal spin-crossover (SCO) behavior with the characteristic temperature T-1/2 dependent on the guest molecule, whereas the guest-free species 1 is paramagnetic whatever the temperature. For the benzene-guest derivatives, the characteristic SCO temperature T-1/2 decreases as the Hammet sigma(p) parameter increases. In general, the 1@guest series shows large entropy variations associated with the SCO and conformational changes of the interpenetrated grids that leads to a crystallographic-phase transition when the guest is benzonitrile or acetonitrile/H2O., The research reported herein was supported by the Spanish Ministerio de Economia y Competitividad (MINECO) and FEDER funds (CTQ2013-46275-P; MAT2012-34740), the Basque Government (project IT-779-13), and Generalitat Valenciana (PROMETEO/2012/049). T.R.M. thanks the Spanish Ministerio de Economia y Competitividad (MINECO) for a predoctoral grant (FPI.). L.P.-L. thanks the Generalitat Valenciana for a predoctoral fellowship in the frame of the project PROMETEO/2012/049.

An organocatalytic enantioselective aza-Friedel–Crafts addition of 2-naphthols to benzoxathiazine 2,2-dioxides is described using a quinine-derived bifunctional catalyst. The method allows the use of a wide range of aromatic compounds as nucleophiles, including 1-naphthol and sesamol, and benzoxathiazines 2,2-dioxides, expanding the existing state of the art enantioselective synthesis of aminomethylnaphthol derivatives.

Solvated and unsolvated forms of the complex [Fe(HAT)(NCS)2]∞·(nMeOH) (1) (n = 1.5, 0; HAT = 1,4,5,8,9,12-hexaazatriphenylene) were prepared. The structure of 1·(1.5MeOH), measured at 120 K, showed that this system crystallizes in the homochiral P43 tetragonal space group. The solid is constituted of stacks of one-dimensional coordination polymers running along c-axis. All the FeII centres have the same Λ or Δ conformation and are in the LS state at 120 K. In the range of temperatures 10–300 K the magnetic properties of 1·(1.5MeOH) shows the occurrence of reversible spin crossover behaviour. However, above ca. 310 K complete desolvation of 1·(1.5MeOH) to give 1 was observed from crystal structure analysis, magnetic behaviour and thermal analysis. Compound 1 displays a two-step spin crossover behaviour characterised by a plateau 60 K wide. Simulation of the two-step behaviour in the frame of the regular solutions theory afforded, respectively, the critical temperatures (Tci), the interaction parameters (Γi), and the enthalpy (ΔHi) and entropy (ΔSi) variations for steps i = 1 and 2: Tc1(Tc2) = 172 (358) K, Γ1(Γ2) = 1.6 (3.0) kJ mol−1, ΔH1(ΔH2) = 5.7 (18.3) kJ mol−1 and ΔS1(ΔS2) = 33.4 (51.0) J K mol−1.

Six clathrate compounds of the three-dimensional spin crossover metal−organic framework formulated [Fe(TPT)2/3{MI (CN)2}2]· nG, where TPT is 2,4,6-tris(4-pyridyl)-1,3,5-triazine, MI = Ag or Au and G represent the guest molecules furan, pyrrole and thiophene, were synthesized using slow diffusion techniques. The clathrate compounds were characterized by single-crystal X-ray diffraction at 120 and 300 K, thermogravimetric analysis and thermal dependence of the magnetic susceptibility. All compounds crystallize in the R3̅ m trigonal space group. The FeII defines a unique [FeN6] crystallographic site with the equatorial positions occupied by four dicyanometallate ligands while the axial positions are occupied by the TPT ligands. Each TPT ligand links three FeII sites, while the dicyanometallate ligands bridge two FeII sites thereby generating two interlocked three-dimensional frameworks with the NbO topology. The choice of the TPT ligand favors the generation of pores where the guest molecules are located. The thermal dependence of the magnetic susceptibility of samples constituted of single crystals was investigated for the six compounds to assess the influence of the guest molecules on the spin crossover behavior. In general, the magnetic properties of the six clathrates suggest a gradual stabilization of the high-spin state as the molecular volume of the guest increases., The research reported here was supported by the Spanish Ministerio de Economia y Competitividad (MINECO) and FEDER funds (CTQ2013-46275-P) and Generalitat Valenciana (PROMETEO/2012/049). Z.A.C. thanks the Spanish M.E.C.D. for a predoctoral FPU fellowship. L.P.L. thanks the Generalitat Valenciana for a predoctoral fellowship in the frame of the project PROMETEO/2012/049.

[EN] The synthesis, crystal structure, magnetic, calorimetric, and Mo¿ ssbauer studies of a series of new Hofmann-type spin crossover (SCO) metal¿organic frameworks (MOFs) is reported. The new SCO-MOFs arise from self-assembly of FeII, bis(4-pyridyl)butadiyne (bpb), and [Ag(CN)2] ¿ or [MII(CN)4] 2¿ (MII = Ni, Pd). Interpenetration of four identical 3D networks with ¿-Po topology are obtained for {Fe(bpb)[AgI (CN)2]2} due to the length of the rod-like bismonodentate bpb and [Ag(CN)2] ¿ ligands. The four networks are tightly packed and organized in two subsets orthogonally interpenetrated, while the networks in each subset display parallel interpenetration. This nonporous material undergoes a very incomplete SCO, which is rationalized from its intricate structure. In contrast, the single network Hofmann-type MOFs {Fe(bpb)[MII(CN)4]}·nGuest (MII = Ni, Pd) feature enhanced porosity and display complete one-step or two-step cooperative SCO behaviors when the pores are filled with two molecules of nitrobenzene or naphthalene that interact strongly with the pyridyl and cyano moieties of the bpb ligands via ¿¿¿ stacking. The lack of these guest molecules favors stabilization of the high-spin state in the whole range of temperatures. However, application of hydrostatic pressure induces one- and two-step SCO., We thank the Spanish Ministerio de Economia y Competitividad (MINECO) and FEDER funds (CTQ2013-46275-P and CTQ2016-78341-P and Unidad de Excelencia Maria de Maeztu MDM-2015-0538) and Generalitat Valenciana (PROMETEO/2016/147). L.P.-L. and F.J.V.-M. thank, respectively, the Universidad de Valencia and MINECO for a predoctoral FPI grant.

A catalytic enantioselective aza-Reformatsky reaction is reported with cyclic dibenzo[b,f][1,4]oxazepines and ethyl iodoacetate leading to the synthesis of chiral ethyl 2-(10,11-dihydrodibenzo[b,f][1,4]oxazepin-11-yl)acetate derivatives with excellent yields and high enantioselectivities (up to 98% yield and 97 : 3 er) using a readily available diaryl prolinol L4 as the chiral ligand and Me2Zn as the zinc source under an air atmosphere. Furthermore, different transformations were carried out with the corresponding chiral β-amino esters, preserving in all cases the optical purity.

[EN] The direct asymmetric Henry reaction with prochiral ketones, leading to tertiary nitroaldols, is an elusive reaction so far limited to a reduced number of reactive substrates such as trifluoromethyl ketones or alpha-keto carbonyl compounds. Expanding the scope of this important reaction, the direct asymmetric addition of nitromethane to 2-acylpyridine N-oxides catalyzed by a BOX-Cu(II) complex to give the corresponding pyridine-derived tertiary nitroaldols having a quaternary stereogenic center with variable yields and good enantioselectivity, is described., Financial support from the Ministerio de Economia y Competitividad (Gobierno de Espana) and FEDER (EU) (CTQ2009-13083) and from Generalitat Valenciana (ACOMP2012-212 and ISIC 2012/001) is acknowledged. M.H. thanks the GV for a predoctoral grant (Santiago Grisolia Program).

Financial support (Grant CTQ2013-47494-P) from the Ministerio de Economia y Competitividad (MINECO-Gobierno de Espana). A.S.M. thanks the MINECO for a predoctoral grant (FPI program). Access to NMR and MS facilities from the Servei Central de Suport a la Investigacio Experimental (SCSIE)-UV is also acknowledged.

The chemisorption of sulfur dioxide (SO2) on the Hofmann-like spin crossover porous coordination polymer (SCO-PCP) {Fe(pz)[Pt(CN)4]} has been investigated at room temperature. Thermal analysis and adsorption-desorption isotherms showed that ca. 1 mol of SO2 per mol of {Fe(pz)[Pt(CN)4]} was retained in the pores. Nevertheless, the SO2 was loosely attached to the walls of the host network and completely released in 24 h at 298 K. Single crystals of {Fe(pz)[Pt(CN)4]}·nSO2 (n ≈ 0.25) were grown in water solutions saturated with SO2, and its crystal structure was analyzed at 120 K. The SO2 molecule is coordinated to the Pt(II) ion through the sulfur atom ion, Pt-S = 2.585(4) Å. This coordination slightly stabilizes the low-spin state of the Fe(II) ions shifting the critical temperatures of the spin transition by 8-12 K. DFT calculations have been performed to rationalize these observations.

A highly enantioselective Friedel–Crafts reaction of unprotected indoles with (E)-1-aryl-4-benzyloxybut-2-en-1-ones catalyzed by a new chiral [Hf{(R)-3,3′-Br2-BINOL}(OtBu)2]2 complex has been developed to functionalize the C-3 position of the indole nucleus with a side chain bearing a 1,4-difunctionalized moiety and a benzylic stereogenic center. The reaction proceeds in good to excellent yields and excellent enantioselectivities (up to 97 % ee). The usefulness of this approach was illustrated with the synthesis of a tryptophol derivative.

Experimental and theoretical studies on the structure of several complexes based on (R)-3,3'-Br-2-BINOL ligand and group (IV) metals used as catalysts in an enantioselective Friedel-Crafts alkylation of indoles with alpha,beta-unsaturated ketones have been carried out. NMR spectroscopic studies of these catalysts have been performed, which suggested that at room temperature the catalysts would form a monomeric structure in the case of Ti-IV and a dimeric structure in the cases of Zr-IV and Hf-IV. Density functional theory (DFT) calculations clearly corroborate the conclusions of these experimental spectroscopic studies. The dimeric structure with a doubly bridged motif [Zr-2(IV)(mu-(R)-3,3'-Br-2-BINOL)(2)] where each binaphthol ligand acts as bridge between the metal centers (Novak's model) is more stable than the dimeric structure with a doubly bridged motif [Zr-2(IV)(mu-(OBu)-Bu-t)(2)] where the tert-butoxide groups act as bridging ligands (Kobayashi's model). The scope of the Friedel-Crafts alkylation with regard to the indole structure has been studied. Finally a plausible mechanism for the Friedel-Crafts reaction and a stereomodel for the mode of action of the catalyst that explain the observed stereochemistry of the reaction products have been proposed., Financial support from the Ministerio de Ciencia e Innovacion, Gobierno de Espana and FEDER, European Union (Grant CTQ 2009-13083) and the Generalitat Valenciana (Grants ACOMP/2012/212 and ISIC 2012/001) is acknowledged. C.V. thanks the Generalitat Valenciana for a predoctoral grant

Financial support from the MINECO (Gobierno de Espana and FEDER (EU)) (CTQ2013-47949-P) and from Generalitat Valenciana (ISIC2012/001) is gratefully acknowledged. C. V. thanks MINECO for JdC contract. Access to NMR, MS and X-ray facilities from the Servei central de support a la investigacio experimental (SCSIE)-UV is also acknowledged.

An efficient one-pot asymmetric synthesis of pyrazoles bearing a chiral quaternary stereocenter has been developed. Quinine-derived thiourea catalyzed the enantioselective addition of pyrazolones to isatin-derived ketimines, providing the corresponding acetylated pyrazoles after in situ treatment with Ac2 O/Et3 N. The corresponding pyrazoles were afforded in high yields and excellent enantioselectivities.

The stereodivergent synthesis of N-tosyl α,β-dehydroamino esters via a Mukaiyama–Michael addition is reported. The reaction of silylketene acetals with N-tosylimines derived from β,γ-unsaturated α-keto esters in dichloromethane provided the corresponding (Z)-α,β-dehydroamino esters while the (E)-isomers were obtained when the reaction was carried out in the presence of 10 mol% copper(II) triflate.

A new enantioselective route to spiro[piperidine-3,3′-oxindoles] from isatin ketimines is described. The aza-Henry reaction of N-Boc-isatin ketimines with methyl 4-nitrobutyrate in the presence of a Ph2BOX-CuBr2 complex provided the corresponding nitro amino esters with good diastereoselectivity and excellent enantioselectivity (up to >99% ee). The aza-Henry adducts were transformed into spiro[piperidine-3,3′-oxindoles] after reduction of the nitro group to oxime, and cleavage of the N-Boc group and lactamisation.

The first catalytic enantioselective conjugate alkynylation of α,β-unsaturated 1,1,1-trifluoromethyl ketones has been carried out. Terminal alkynes and 1,3-diynes were treated with trifluoromethyl ketones in the presence of a low catalytic load of a CuI-MeOBIPHEP complex (2.5 mol %) and triethylamine (10 mol %) to give the corresponding trifluoromethyl ketones bearing a propargylic stereogenic center at the β position with good yields and excellent enantiomeric excesses in most of the cases. No 1,2-addition products were formed under the reaction conditions. The procedure showed broad substrate scope for alkyne, diyne, and enone. A rationale for the observed stereochemistry has been provided. Finally, the potential application of the reaction products in the synthesis of chiral tetrahydrofurans bearing a trifluoromethylated quaternary stereocenter has been devised., Financial support (Grant CTQ2013-47494-P) from the Ministerio de Economia y Competitividad (MINECO-Gobierno de Espana). A.S.M. thanks the MINECO for a predoctoral grant (FPI program). Access to NMR and MS facilities from the Servei Central de Suport a la Investigacio Experimental (SCSIE)-UV is also acknowledged.