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Trap-assisted non-radiative recombination losses and moisture-induced degradation significantly impede the development of highly efficient and stable inverted (p-i-n) perovskite solar cells (PSCs), which require high-quality perovskite bulk. In this research, we mitigate these challenges by integrating thermally stable perovskite layers with Lewis base covalent organic frameworks (COFs). The ordered pore structure and surface binding groups of COFs facilitate cyclic, multi-site chelation with undercoordinated lead ions, enhancing the perovskite quality across both its bulk and grain boundaries. This process not only reduces defects but also promotes improved energy alignment through n-type doping at the surface. The inclusion of COF dopants in p-i-n devices achieves power conversion efficiencies (PCEs) of 25.64 % (certified 24.94 %) for a 0.0748-cm 2 device and 23.49 % for a 1-cm 2 device. Remarkably, these devices retain 81 % of their initial PCE after 978 hours of accelerated aging at 85°C, demonstrating remarkable durability. Additionally, COF-doped devices demonstrate excellent stability under illumination and in moist conditions, even without encapsulation., (© 2024 Wiley-VCH GmbH.)

Gallylene supported by a bis(oxazolinyl)(phenyl)methanide (Boxm) ligand was synthesized and structurally characterized. The reaction of this gallylene with triphenylphosphine sulfide/selenide yielded dimeric gallium sulfide and selenide. These compounds could be converted to monomeric terminal sulfide and selenide by coordination of an external Lewis base such as an N-heterocyclic carbene (NHC or IMe 4 ) and 4-dimethylaminopyridiene (DMAP). These doubly-base-stabilized gallium sulfide/selenide reacted with phenyl isocyanate to give the corresponding cycloadducts by releasing the Lewis base, indicating the formation of a single-base-stabilized gallium sulfide/selenide intermediate., (© 2024 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)

We report the preparation of a new organic σ-donor with a C 6 H 4 -linker between an N-heterocyclic carbene (NHC) and an exocyclic methylidene group, which we term N-heterocyclic quinodimethane (NHQ). The aromatization of the C 6 H 4 -linker provides a decisive driving force for the reaction of the NHQ with an electrophile and renders the NHQ significantly more basic than analogous NHCs or N-heterocyclic olefins (NHOs), as shown by DFT computations and competition experiments. In solution, the NHQ undergoes an unprecedented dehydrogenative head-to-head dimerization by C-C coupling of the methylidene groups. DFT computations indicate that this reaction proceeds via an open-shell singlet pathway revealing the diradical character of the NHQ. The product of this dimerization can be described as conjugated N-heterocyclic bis-quinodimethane, which according to cyclic voltammetry is a strong organic reducing agent (E 1/2 =-1.71 V vs. Fc/Fc + ) and exhibits a remarkable small singlet-triplet gap of ΔE S→T =4.4 kcal mol -1 ., (© 2023 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

The dinuclear bis(N-heterocyclic carbene) borane adduct 2 rapidly reacts with tritylium salts at room temperature but the outcome is strongly impacted by the respective counter-ion. Using tritylium tetrakis(perfluoro-tert-butoxy)aluminate affords - depending on the solvent - either the bis(boronium) ion 4 or the hydride-bridged dication 5. In case of tritylium hexafluorophosphate, however, H/F exchange occurs between boron and phosphorus yielding the dinuclear BF 3 adduct 3 along with phosphorus dihydride trifluoride. H/F exchange also takes place when using the mononuclear N-heterocyclic carbene BH 3 adduct 6 and hence provides a facile route to PH 2 F 3 , which is usually synthesized in more complex reaction sequences regularly involving toxic hydrogen fluoride. DFT calculations shed light on the H/F exchange between the borenium ion and the [PF 6 ] - counter-ion and the computed mechanism features only small barriers in line with the experimental observations., (© 2023 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)

We have quantum chemically studied the influence of ring strain on the competition between the two mechanistically different S N 2 and E2 pathways using a series of archetypal ethers as substrate in combination with a diverse set of Lewis bases (F - , Cl - , Br - , HO - , H 3 CO - , HS - , H 3 CS - ), using relativistic density functional theory at ZORA-OLYP/QZ4P. The ring strain in the substrate is systematically increased on going from a model acyclic ether to a 6- to 5- to 4- to 3-membered ether ring. We have found that the activation energy of the S N 2 pathway sharply decreases when the ring strain of the system is increased, thus on going from large to small cyclic ethers, the S N 2 reactivity increases. In contrast, the activation energy of the E2 pathway generally rises along this same series, that is, from large to small cyclic ethers. The opposing reactivity trends induce a mechanistic switch in the preferred reaction pathway for strong Lewis bases from E2, for large cyclic substrates, to S N 2, for small cyclic substrates. Weak Lewis bases are unable to overcome the higher intrinsic distortivity of the E2 pathway and, therefore, always favor the less distortive S N 2 reaction., (© 2023 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)

Hydrosilylation reactions are commonly used for the reduction of carbonyl bonds in fine chemistry, catalyzed by transition metal complexes. The current challenge is to expand the scope of metal-free alternative catalysts, including in particular organocatalysts. This work describes the organocatalyzed hydrosilylation of benzaldehyde with a phosphine, introduced at 10 mol%, and phenylsilane at room temperature. The activation of phenylsilane was highly dependent on the physical properties of the solvent such as the polarity, and the highest conversions were obtained in acetonitrile and propylene carbonate with yields of 46 % and 97 %, respectively. The best results of the screening over 13 phosphines and phosphites were obtained with linear trialkylphoshines (PMe 3 , P n Bu 3 , POct 3 ), indicating the importance of their nucleophilicity, with yields of 88 %, 46 % and 56 %, respectively. With the help of heteronuclear 1 H- 29 Si NMR spectroscopy, the products of the hydrosilylation (PhSiH 3-n (OBn) n ) were identified, allowing a monitoring of the concentration in the different species, and thereby of their reactivity. The reaction displayed an induction period of ca. 60 min, followed by the sequential hydrosilylations presenting various reaction rates. In agreement with the formation of partial charges in the intermediate state, we propose a mechanism based on a hypervalent silicon center via the Lewis base activation of the silicon Lewis acid., (© 2023 The Authors. ChemPlusChem published by Wiley-VCH GmbH.)

We report herein a new method for the synthesis of densely functionalized chiral allyl SCF 3 , SCF 2 R, SCN and SAr species with a separate CF 3 functionality. The synthetic approach is based on selenium-catalyzed sulfenofunctionalization of chiral α-CF 3 allylboronic acids. The reactions proceeded with remarkably high stereo-, diastereo- and site-selectivity, based on the formation of a stable thiiranium ion followed by rapid deborylative ring opening., (© 2022 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

The hydrogen evolution and dendrite issues are the notorious culprits of the limited lifespan and Coulombic efficiency (CE) of Zn anodes, particularly at harsh test conditions. Herein, considering the Lewis acidic feature of Zn 2+ , abundant unshared pair electrons of zincophilic Lewis bases are proposed as decent electrolyte additives to stabilize Zn anodes at "Three High" conditions (high depth of discharge, high areal capacity and high current). The unshared pair electrons can remove H 2 O from Zn 2+ solvated sheaths and confine the activity of H 2 O by breaking its hydrogen bonding network. The combination of these factors effectively restricts H 2 O-involved side reactions and enables dendrite-free Zn deposition, even at harsh conditions. The effectiveness of this strategy is fully proved by a series of Lewis base molecules. Noticeably, the Zn||Zn cell with an area of 20 cm 2 , using DMF-containing electrolyte can be stably cycled over 1000 h at 60 % DOD, with a 100 % CE., (© 2022 Wiley-VCH GmbH.)

While the addition of C1-Lewis base enolates to carbonyls and related structures are well established, the related addition to thiocarbonyls compounds are unknown. Herein, we report a reaction cascade in which a C1-pyridinium enolate undergos addition to dithioesters, trithiocarbonates and xanthates. The reaction provides access to a range of dihydrothiophenes and dihydrothiopyrans (28-examples). Mechanistic investigations, including isolation of intermediates, electronic correlation, and kinetic isotope effect studies support the viability of an activated acid intermediate giving rise to the C1-pyridinium enolate which undergoes turnover limiting cyclization. Subsequent formation of a β-thiolactone regenerates the catalyst with loss of carbon oxysulfide providing the observed products., (© 2022 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

The Group 15 Pn(I) cations (Pn=N, P, As, Sb and Bi), which are isoelectronic with the donor-stabilized carbones, have emerged recently. Despite the presence of two lone pair of electrons, the Pn(I) cations are weakly nucleophilic due to their inherent positive charge. Strongly electron-donating supporting ligands including zwitterionic forms have been used to enhance their Lewis basicity. Furthermore, the chelating effect of cyclic ligand systems proved effective in increasing their nucleophilicity. The strategies involved in successfully isolating the fleeting Sb(I) and Bi(I) cations as the recent most achievements in this field have been discussed. The syntheses, structure, bonding situations and reactivity of the Pn(I) cations are discussed. An outlook on the periodic trends and future applications of these electronically unique electron-rich cationic moieties have been provided., (© 2021 Wiley-VCH GmbH.)

This Minireview provides insight into the early history of nucleophilic phosphinocatalysis. The concepts of 1,4-addition of a tertiary phosphine to an α,β-enone and of equilibrium between the resulting phosphonium zwitterion and phosphonium ylide established a fundamental basis for the development of several classical transformations, including the Rauhut-Currier, Morita, McClure-Baizer-Anderson, and Oda reactions., Competing Interests: Conflict of Interest The authors declare no conflict of interest.

Solvent engineering by Lewis-base solvent and anti-solvent is well known for forming uniform and stable perovskite thin films. The perovskite phase crystallizes from an intermediate Lewis-adduct upon annealing-induced crystallization. Herein, it is explored the effects of trimethyl phosphate (TMP), as a novel aprotic Lewis-base solvent with a low donor number for the perovskite film formation and photovoltaic characteristics of perovskite solar cells (PSCs). As compared to dimethylsulfoxide (DMSO) or dimethylformamide (DMF), the usage of TMP directly crystallizes the perovskite phase, i.e., reduces the intermediate phase to a negligible degree, right after the spin-coating, owing to the high miscibility of TMP with the anti-solvent and weak bonding in the Lewis adduct. Interestingly, the PSCs based on methylammonium lead iodide (MAPbI 3 ) derived from TMP/DMF-mixed solvent exhibit a higher average power conversion efficiency of 19.68% (the best: 20.02%) with a smaller hysteresis in the current-voltage curve, compared to the PSCs that are fabricated using DMSO/DMF-mixed (19.14%) or DMF-only (18.55%) solvents. The superior photovoltaic properties are attributed to the lower defect density of the TMP/DMF-derived perovskite film. The results indicate that a high-performance PSC can be achieved by combining a weak Lewis base with a well-established solvent engineering process., (© 2021 The Authors. Advanced Science published by Wiley-VCH GmbH.)

The unique three-dimensional structure of spherical, homoatomic nine-atom germanium clusters opens various possibilities for the spatial arrangement of functional groups. Ligands comprising lone pairs have recently been introduced in the cluster sphere, and we now report the addition of a boranyl group to the cluster featuring a Ge-B exo-cluster bond. The reaction of the twofold-silylated cluster [Ge 9 {Si(TMS) 3 } 2 ] 2- (TMS=trimethylsilyl) with 2-chloro-1,3,2-diazaborolidines DAB R -Cl leads to the first boranyl-functionalized [Ge 9 ] clusters [Ge 9 {Si(TMS) 3 } 2 DAB R ] - (R=methyl (1 a), iso-propyl (2 a), ortho-tolyl (3 a)). The anions 2 a and 3 a were structurally characterized as [NHC Dipp Cu] + complexes (NHC Dipp =1,3-di(2,6-diisopropylphenyl)imidazolylidine) through single crystal X-ray structure determination. Quantum-chemical calculations manifest the frustrated Lewis pair (FLP) character of the boranyl-functionalized cluster [Ge 9 {Si(TMS) 3 } 2 BCy 2 ] - (4 a)., (© 2020 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

The concept of frustrated Lewis pairs (FLPs) has been widely applied in various research areas, and metal-free hydrogenation undoubtedly belongs to the most significant and successful ones. In the past decade, great efforts have been devoted to the synthesis of chiral boron Lewis acids. In a sharp contrast, chiral Lewis base derived FLPs have rarely been disclosed for the asymmetric hydrogenation. In this work, a novel type of chiral FLP was developed by simple combination of chiral oxazoline Lewis bases with achiral boron Lewis acids, thus providing a promising new direction for the development of chiral FLPs in the future. These chiral FLPs proved to be highly effective for the asymmetric hydrogenation of ketones, enones, and chromones, giving the corresponding products in high yields with up to 95 % ee. Mechanistic studies suggest that the hydrogen transfer to simple ketones likely proceeds in a concerted manner., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A family of gyroidal metal-organic frameworks (STUs) composited with transition metal ions and bi-imidazolate ligands (BIm) were prepared and applied as both Lewis base and acid catalysts. Benefiting from the intrinsic basicity of the ligands and the Lewis acidic sites of the open metal centres, the STUs materials show excellent catalytic activities as Lewis base for the Knoevenagel condensation reaction between various aldehydes and malononitrile, and as Lewis acid for cyanosilylation reactions. Among these STUs, STU-4 (Ni(BIm)) shows the best catalytic efficiency (conversions >99 %) in both Knoevenagel condensation and cyanosilylation reactions under mild conditions, providing thus an advanced material for both Lewis base and Lewis acid catalysis., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Auto-tandem catalysis (ATC), in which a single catalyst promotes two or more mechanistically different reactions in a cascade pattern, provides a powerful strategy to prepare complex products from simple starting materials. Reported here is an unprecedented auto-tandem cooperative catalysis (ATCC) for Morita-Baylis-Hillman carbonates from isatins and allylic carbonates using a simple Pd(PPh 3 ) 4 precursor. Dissociated phosphine generates phosphorus ylides and the Pd leads to π-allylpalladium complexes, and they undergo a γ-regioselective allylic-allylic alkylation reaction. Importantly, a cascade intramolecular Heck-type coupling proceeds to finally furnish spirooxindoles incorporating a 4-methylene-2-cyclopentene motif. Experimental results indicate that both Pd and phosphine play crucial roles in the catalytic Heck reaction. In addition, the asymmetric versions with either a chiral phosphine or chiral auxiliary are explored, and moderate results are obtained., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The strained olefins in trans-cyclooctenes serve as efficient catalysts for halolactonizations, including bromolactonizations and iodolactonizations. The trans-cyclooctene framework is essential for excellent catalytic performance, and the substituents also play important roles in determining efficiency. These results are the first demonstration of catalysis by a trans-cyclooctene., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The reaction of a pentamethylcyclopentadienyl-substituted dialane with a variety of Lewis bases results in unexpected disproportionation of the dialane into Al I and Al III species. Use of a transition-metal Lewis base allows for the formation of metal-only Lewis pairs. Furthermore, the synthesis of a Lewis base bis-adduct was successful with the Lewis base 4-dimethylaminopyridine., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Lewis base-borane complexes are shown to be potent hydrogen atom donors in radical chain reduction reactions. Results obtained in 1 H, 11 B, and 13 C NMR measurements and kinetic experiments support a complex reaction mechanism involving the parent borane as well as its initial reaction products as active hydrogen atom donors. Efficient reduction reactions of iodides, bromides, and xanthates in apolar solvents rely on initiator systems generating oxygen-centered radicals under thermal conditions and pyridine-borane complexes carrying solubilizing substituents. In contrast to tin hydride reagents, the pyridine-boranes reduce xanthates faster than the corresponding iodides., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Brønsted acidification of water by Lewis acid (LA) complexation is one of the fundamental principles in chemistry. Using transition-state calculations (TS), herein we investigate the role that Brønsted acidification of the LA-bound water might play in the mechanism of the hydrogenation of carbonyl compounds in Lewis basic solvents under non-anhydrous conditions. The potential energy scans and TS calculations were carried out with a series of eight borane LAs as well as the commonly known strong LA AlCl 3 in 1,4-dioxane or THF as Lewis basic solvents. Our molecular model consists of the dative LA-water adduct with hydrogen bonds to acetone and a solvent molecule plus one additional solvent molecule that participates is the TS structure describing the cleavage of H 2 at acetone's carbonyl carbon atom. In all the molecular models applied here, acetone (O=CMe 2 ) is the archetypical carbonyl substrate. We demonstrate that Brønsted acidification of the LA-bound water can indeed lower the barrier height of the solvent-involving H 2 -cleavage at the acetone's carbonyl carbon atom. This is significant because at present it is believed that the mechanism of the herein considered reaction is described by the same mechanism regardless of whether the reaction conditions are strictly anhydrous or non-anhydrous. Our results offer an alternative to this belief that warrants consideration and further study., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

It is well known that the surface trap states and electronic disorders in the solution-processed CH 3 NH 3 PbI 3 perovskite film affect the solar cell performance significantly and moisture sensitivity of photoactive perovskite material limits its practical applications. Herein, we show the surface modification of a perovskite film with a solution-processable hydrophobic polymer (poly(4-vinylpyridine), PVP), which passivates the undercoordinated lead (Pb) atoms (on the surface of perovskite) by its pyridine Lewis base side chains and thereby eliminates surface-trap states and non-radiative recombination. Moreover, it acts as an electron barrier between the perovskite and hole-transport layer (HTL) to reduce interfacial charge recombination, which led to improvement in open-circuit voltage (V oc ) by 120 to 160 mV whereas the standard cell fabricated in same conditions showed V oc as low as 0.9 V owing to dominating interfacial recombination processes. Consequently, the power conversion efficiency (PCE) increased by 3 to 5 % in the polymer-modified devices (PCE=15 %) with V oc more than 1.05 V and hysteresis-less J-V curves. Advantageously, hydrophobicity of the polymer chain was found to protect the perovskite surface from moisture and improved stability of the non-encapsulated cells, which retained their device performance up to 30 days of exposure to open atmosphere (50 % humidity)., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

In contrast to the well-studied asymmetric catalyzed synthesis of tetrahydroquinolines, the asymmetric methodologies toward 3,4-dihydroquinolin-2-ones are quite rare. Herein, the first asymmetric cascade reaction is reported between ethynyl benzoxazinanones and mixed-anhydrides generated from aryl acetic acids and pivaloyl chloride, based on synergistic catalysis. This allowed the formation of attractive 3,4-dihydroquinolin-2-ones bearing two vicinal chiral centers at C3 and C4 in high yields with excellent diastereo- and enantioselectivities. A plausible chiral induction model for this reaction was proposed. The utility of this methodology was exemplified by further elaboration of the cyclization products by removal of the N-protecting groups., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The generation of in situ sp 2 -sp 3 diboron adducts has revolutionised the synthesis of organoboranes. Organocatalytic diboration reactions have represented a milestone in terms of unpredictable reactivity of these adducts. However, current methodologies have limitations in terms of substrate scope, selectivity and functional group tolerance. Here a new methodology based on the use of simple amines as catalyst is reported. This methodology provides a completely selective transformation overcoming current substrate scope and functional/protecting group limitations. Mechanistic studies have been included in this report., (© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

α,β-Unsaturated acyl ammoniums generated from the reaction of α,β-unsaturated 2,4,6-trichlorophenol (TCP) esters bearing a pendent enone with an isothiourea organocatalyst are versatile intermediates in a range of enantioselective nucleophile-dependent domino processes to form complex products of diverse topology with excellent stereoselectivity. Use of either 1,3-dicarbonyls, acyl benzothiazoles, or acyl benzimidazoles as nucleophiles allows three distinct, diastereodivergent domino reaction pathways to be accessed to form various fused polycyclic cores containing multiple contiguous stereocentres., (© 2016 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.)

Density functional theory (DFT) investigations revealed that 4-cyanopyridine was capable of homolytically cleaving the B-B σ bond of diborane via the cooperative coordination to the two boron atoms of the diborane to generate pyridine boryl radicals. Our experimental verification provides supportive evidence for this new B-B activation mode. With this novel activation strategy, we have experimentally realized the catalytic reduction of azo-compounds to hydrazine derivatives, deoxygenation of sulfoxides to sulfides, and reduction of quinones with B2 (pin)2 at mild conditions., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The N-heterocyclic carbene (NHC) catalyzed redox formal [2+2] cycloaddition between α-aroyloxyaldehydes and perfluoroketones, followed by ring-opening in situ delivers a variety of perfluorinated β-hydroxycarbonyl compounds in good yield, and excellent diastereo- and enantioselectivity. Through a reductive work-up and subsequent cyclization, this protocol offers access to highly substituted fluorinated oxetanes in two steps and in high ee., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The reaction of the functionalized cyclo-tetraphosphane [ClP(μ-PMes*)]2 (Mes*=2,4,6-tri-tert-butylphenyl) with different Lewis bases led to the formation of an unprecedented tricyclic hexaphosphane, Mes*P6 Mes*. The formation of this compound was investigated by spectroscopic and theoretical methods, revealing an unusual ring expansion reaction. The title compound was fully characterized by experimental and computational methods., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A highly enantioselective Lewis base-catalysed formal [3+2] cycloaddition of ammonium enolates and oxaziridines to give stereodefined oxazolidin-4-ones in high yield is described. Employing an enantioenriched oxaziridine in this process leads to a matched/mis-matched effect with the isothiourea catalyst and allowed the synthesis of either syn- or anti-stereodefined oxazolidin-4-ones in high d.r., yield and ee. Additionally, the oxazolidin-4-one products have been derivatised to afford functionalised enantioenriched building blocks., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A highly enantioselective β-isocupreidine (β-ICD) catalyzed synthesis of dihydropyran-fused benzofurans through [4+2] cycloaddition of allenoates and benzofuranone alkenes was developed. Switchable chirality inversion of cycloaddition products was achieved by replacing the phenolic proton of the catalyst with a methyl, demonstrating an amazing effect of minimal structural variation on inverting enantioselectivity. DFT calculations were utilized to elucidate the origin of the observed phenomena. Computation also provided a clue for a rational design in which the multi-hydrogen bond with the alcohol additive was found to improve the enantioselectivity of the cycloaddition. Finally, the substrate scope was examined, in which a number of functionalized dihydropyran-fused benzofurans could be obtained in high yields (up to 97 %) with very good regio- (>20:1) and enantioselectivities (up to 98:2 e.r.)., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Allylation, trans- and cis-crotylation of (2E,4E)-2,4-dimethylhexadienal, a representative α,β,γ,δ-unsaturated aldehyde, was carried out under different catalytic and stoichiometric conditions. The reactions catalyzed by organocatalysts TRIP-PA and N,N'-dioxides gave the best results with respect to yields, asymmetric induction, and catalyst load in comparison to other procedures. The developed methodology was applied in the enantioselective synthesis of (5R,6S)-(+)-pteroenone, a defensive metabolite (ichthyodeterrent) of the Antarctic pteropod Clione antarctica., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The discovery of a novel aerobic oxidative intermolecular azide-zwitterion reaction catalyzed by an organocatalyst is presented. It is demonstrated that the merger of the Lewis base 1,8-diazabicyclo[5.4.0]undec-7-ene and electron-deficient olefins generates reactive zwitterion intermediates, which readily participate in cycloaddition reactions with an array of azides, thus providing facile entry to fully or highly substituted 1,2,3-triazole frameworks. The reaction features an excellent substrate scope, and the products are obtained with high yields and excellent regioselectivities. It is demonstrated that some of these products can be transformed into pharmaceutically important agents. In addition to the experimental results, a detailed mechanistic survey is also provided, including MS studies rationalizing the origin of regioselective control., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A facile, efficient, and highly diastereo- and enantioselective bromoetherification of diolefinic diols has been developed using an amino-thiocarbamate catalyst. Further manipulations of the bromoether products enabled entry into a new class of spirocycles which are distinctively lacking in the literature., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Acids to bases: The synthesis of 2,4,6-trisubstituted pyridines from (phenylthio)acetic acid and a range of α,β-unsaturated ketimines is reported. This process proceeds by intermolecular Michael addition/lactamization, thiophenol elimination, and N- to O-sulfonyl migration, giving 2-sulfonate-substituted pyridines which are readily derivatized to generate structural diversity., (© 2013 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.)