Search

The transition-metal-catalyzed synthesis of chiral silacycles is a challenging processes in organosilicon chemistry. Herein, we report a facile and regioselective synthesis of a novel class of 2,3-dihydrosilole derivatives with good yields via the palladium-catalyzed Heck-type reaction of silacyclopentenes (SCPs) with aryl iodides. Preliminary investigations on the enantioselective version of this palladium-catalyzed Heck-type process reveal that the presence of N-Boc-l-proline allows the diastereo- and enantioselective formation of chiral 2,3-dihydrosilole derivatives bearing both carbon and silicon-stereogenic centers.

An iridium-catalyzed, directing group-enabled site selective intra- and intermolecular silylation of indoles and pyrroles with hydrosilanes has been developed under ligand-free conditions. Fine-tuning of the removable 3-alkyl-2-pyridyl directing group was found to be crucial for achieving high yields for C2-silylated indole and pyrrole products. Moreover, the scalability was demonstrated, and further transformations of the silylation products were achieved.

ConspectusEnantiopure atropisomers have become increasingly important in asymmetric synthesis and catalysis, pharmaceutical science, and material science since the discovery of inherent features of axial chirality originating from rotational restriction. Despite the advances made in this field to date, it remains highly desirable to construct structurally diverse atropisomers with potentially useful functions. We propose superposition to match axial and point chirality as a potentially useful strategy to access structurally complex and diverse building blocks for organic synthesis and pharmaceutical science because merging atropisomeric backbones with one or more extra chiral elements can topologically broaden three-dimensional environments to create complex scaffolds with multiple tunable parameters. Over the past decade, we have successfully implemented a strategic design for the superposition of axial and point chirality to develop a series of enantiopure atropisomers and have utilized the synergistic functions of these molecules to enhance chirality transfer in various catalytic asymmetric transformations.In this Account, we present several novel atropisomers with superposed axial and point chirality developed in our laboratory. In our studies, this superposition strategy was used to design and synthesize both biaryl and non-biaryl atropisomers from commercially available chiral sources. Consequently, these atropisomers were used to demonstrate the importance of the synergetic functions of axial and point chirality in specific enantioselective reactions. For example, aromatic amide-derived atropisomers, simplified as Xing-Phos arrays, were broadly employed in Ag-catalyzed [3 + 2] cycloaddition by a series of reactions of aldiminoesters with activated alkenes and imines, as well as being used as chiral solvating agents for the discrimination of optically active mandelic acid derivatives. Considering the powerful potential of non-biaryl atropisomers for asymmetric catalysis, we also explored the transition-metal-catalyzed enantioselective construction of a novel backbone of non-biaryl atropisomers (Ar-alkene, Ar-N axis) bearing both axial and point chirality for the design and synthesis of chiral ligands and functional molecules.The studies presented herein are expected to stimulate further research efforts on the development of functional atropisomers by superposition of matching axial and point chirality. In addition to tunable electron and stereohindrance effects, the synergy between matching chiral elements of axial/point chirality and functional groups is proven to be a special function that cannot be ignored for promoting reactivity and chirality-transfer efficiency in enantioselective synthesis. Consequently, our novel types of scaffolds with superposed axial and point chirality that are capable of versatile coordination with various metal catalysts in asymmetric catalysis highlight the power of the superposition of matching axial and point chirality for the construction of synthetically useful atropisomers.

Although palladium-catalyzed asymmetric C-H functionalization and Heck reactions represents one of the most important synthetic strategies for the construction of quaternary stereocenters, developing the enantioselective version of Pd

The catalytic asymmetric synthesis of novel and chiral amino acid derivatives with unconventional chemo-, diastereo-, and enantio-selectivity remains a paramount challenge. Herein we reported a novel protocol for the use of highly enantioselective copper-catalyzed cycloaddition of α,β-unsaturated acylsilanes as a springboard reaction for the facile synthesis of structurally diversified pyrrolidines and complicated α-amino esters by desilylation. The newly developed process could provide a wide range of synthetically useful acylsilane-substituted pyrrolidines (ASiP) in high yields and excellent diastereo- and enantio-selectivities with Cu/(R)-XylBINAP complex as the catalyst. And the downstream desilylation transformation enables to expand the potntial applications of 1,3-dipolar cycloaddition in the construction of structurally unique amino acid derivatives, in which an unprecedented and concerted fluoride anion-promoted C–X (X=H, Si, N, C) bond cleavage occurred to the enantioselective construction of aldehyde-substituted pyrrolidines, linear cinnamaldehyde or alkene-substituted amino esters in high ee values.

Catalytic hydrosilylation of alkenes ranks as one of the most important academic and industrial synthetic reactions in homogeneous catalysis and organosilicon chemistry. In this work, a highly enan...

A convenient and efficient three-step synthesis of 2-(2,2-difluoroethoxy)-6-(trifluoromethyl)benzenesulfonyl chloride, the key building block of penoxsulam, is described. The main features of the synthesis include a regioselective lithiation and subsequent electrophilic substitution starting from commercially available 3-bromobenzotrifluoride to provide (2-bromo-6-(trifluoromethyl)phenyl)(propyl)sulfane, then a copper-catalyzed C–O coupling to introduce the difluoroethoxy moiety and chloroxidation conditions to give the desired sulfonyl chloride.

A palladium-catalyzed chelation-assisted enantioselective C-H olefination of symmetrically diaryl-substituted tetraorganosilicon derivatives was developed, enabling the generation of nitrogen-containing silicon-stereogenic tetraorganosilicon compounds with modest to good yields and good to excellent enantioselectivities (up to 95.5:4.5 e.r.). The Thorpe-Ingold effect exerted by the substituents on silicon was observed to have a profound influence on formation of olefinated products which were further converted into other relevant chiral organosilanes without the loss of enantiomeric purity, thus demonstrating the synthetic utility of the developed enantioselective olefination.

A unique 1,3-dipolar [3+2] cycloaddition of alkyl 4-oxo-4-arylbut-2-enoates bearing two different electron-withdrawing groups was completed by using the silver/(R)-DTBM-Segphos catalyst system, which gives the corresponding fully substituted pyrrolidines with four stereogenic centers in good yields and with excellent enantioselectivities (up to 98% ee).

The first example of palladium-catalyzed chelation-assisted C–H olefination of 2-amino biaryls using readily available vinylsilanes as unactivated olefinating reagents has been developed, affording valuable arylated vinylsilane compounds in moderate to excellent yields and with exclusive (E)-selectivities.

Although asymmetric C-H functionalization has been available for the synthesis of structurally diverse molecules, catalytic dynamic kinetic resolution (DKR) approaches to change racemic stereogenic axes remain synthetic challenges in this field. Here, a concise palladium-catalyzed DKR was combined with C-H functionalization involving olefination and alkynylation for the highly efficient synthesis of non-biaryl-atropisomer-type (NBA) axially chiral oragnosilanes. The chemistry proceeded through two different and distinct DKR: first, an atroposelective C-H olefination or alkynylation produced axially chiral vinylsilanes or alkynylsilanes as a new family of non-biaryl atropisomers (NBA), and second, the extension of this DKR strategy to twofold o,o'-C-H functionalization led to the multifunctional axially chiral organosilicon compounds with up to >99 % ee.

A highly diastereo- and enantioselective silver-catalyzed azomethine ylide-imine (AYI) cycloaddition reaction of glycine aldimino esters with imines was developed in which the Xing-Phos-controlled syn-selective or DTBM-Segphos-induced anti-selective AYI cycloaddition reaction could be applied to the synthesis of a variety of stereodivergent 1-alkyl-2,5-substituted imidazolidines with high yields and excellent enantioselectivities (up to 99% ee) as well as good diastereoselectivities (up to 99:1 dr) under mild reaction conditions.

An atom-economical strategy for the synthesis of functionalized alkylidenecyclobutanes (ACBs) via Lewis acid-catalyzed yne-carbonyl metathesis of ynamides and cyclobutanones is described. This strategy features mild reaction conditions, ready availability of starting materials, and broad functional group tolerability. Furthermore, the imide group is easily converted to acid, ester, and amide, thus providing an efficient access to various functionalized ACBs.

The use of chiral ligands to tune the reactivity and enantioselectivity of transition metal catalyst for asymmetric transformations is a central challenge in synthetic organic chemistry. In this manuscript, chiral P-ligand (Tao-Phos) -assisted Cu2O nanoparticles -catalyzed asymmetric azide-alkyne Huisgen cycloaddition was successfully reported, in which the unique features of Tao-Phos was determined in copper-catalyzed desymmetrization of pyrazolone -derived bisalkynes via catalytic asymmetric Huisgen [3+2] cycloaddition (CAHC). And it was found that this CAHC transformation resulted in good yields with moderate to high enantioselectivities.

A facile synthesis of γ,δ-unsaturated ketones via palladium-catalyzed ring-opening of 2-alkylidenecyclobutanols with organic halides is described. The key step involves Csp3-Csp2 bond cleavage via palladium-catalyzed β-carbon elimination. The desired γ,δ-unsaturated ketones are obtained in good to excellent yields and broad functional group tolerability. Aryl, heteroaryl, benzyl, and alkynyl halides all readily participate to forge tri-substituted carbon-carbon double bond in a stereoselective manner.

Enantioselective synthesis of chiral heterocycle derivatives is an important and challenging topic in the field of synthetic chemistry. In this work, the first stereocontrolled dimerization-type homo-1,3-polar [3+2] cycloaddition reaction of glycine aldimino esters for creating new heterocycles bearing multiple stereogenic centers has been developed through the chiral phosphine ligand –involved silver catalysis. A variety of chiral imidazolidines could be obtained with high yields and good diastereoselectivities as well as excellent enantioselectivities by employing Xing-Phos as chiral P-ligand.

A new method for the hydrosilylation of alkynes controlled by a platinum catalyst with a monophosphine ligand (called TBSO-MOP) was explored. The platinum-catalyzed multicomponent and sequential silylation reaction involving alkynes, alcohols, and dihydrosilanes resulted in the highly stereoselective and high-yielding construction of functional (E)-vinylsilyl ethers. Moreover, the one-pot bis-hydrosilylation of terminal alkynes with dihydrosilanes was also achieved with the same platinum catalyst system.

Catalytic C-H silylation is an increasingly important topic in the field of organosilicon chemistry and homogenous catalysis as well as organic synthesis, but its synthesis and transformation is usually challenging and often incompatibility with some functional groups. In this manuscript, a new type of silanol-directed intramolecular dehydrogenative silylation under iridium catalysis has been developed. The described silylative cyclization had good functional group compatibility, providing a general and efficient route to unsymmetric cyclic siloxanes with multiple potentially modifiable silicon atoms in high site-selectivities. The resulting organosilicon compounds exhibited diverse synthetic applications owing to their unique structures.

A palladium-catalyzed intramolecular direct arylation reaction of o-bromoaryl phosphine oxides was developed to afford a variety of P-stereogenic phosphole oxides in good yields. The enantioselectivities were closely associated with the specific structures of substrates, which ranged from 4–94%. As a result of ready availability of starting materials and simple operation to improve the enantioselectivities of the products with low ee values, the method provides a simple and straightforward procedure for the synthesis of P-stereogenic phosphole oxides.

Direct functionalization of terpyridines is an increasingly important topic in the field of dyes and catalysis as well as supramolecular chemistry, but its synthesis and transformation is usually challenging. Herein, a HOMO-raising strategy is reported for the construction of a super-stable novel terpyridine chromophores, in which the selective oxidation of terpyridines at its 3-position was determined successfully to the synthesis of phenol-functionalization of terpyridines (TPyOHs) bearing a hydrogen bonding group. The corresponding TPyOHs displayed strong aggregation-induced emission and exhibited highly selective and visual detection of ZnII cation with a record green terpyridine-based luminophore with nanomolar sensitivity (125 nm).

Chiral Si-, P-, and S-containing organic compounds with central, planar, and axial chiralities have found a plethora of applications in various fields of chemistry. Despite significant efforts to explore new catalytic methodologies and synthetic applications to access such compounds, there are still only a few examples which are low in number and limited in diversity. The catalytic construction of Si-, P-, and S-stereogenic organoheteroatom compounds is undoubtedly one of the most exciting and challenging aspects in asymmetric catalysis and the application of catalytic asymmetric C–H activation reaction for the construction of chiral organoheteroatom compounds is still in its infancy. In this Review, we highlighted the main progress on the corresponding catalytic asymmetric reactions that apply to the construction of Si-, P-, and S-stereogenic centers and related chiral organoheteroatom compounds in a catalytic C–H activation fashion.

The catalytic asymmetric copper-catalyzed conjugate addition of diethylzinc to α,β-unsaturated acylsilanes was found to proceed smoothly in moderate to good yields and promising enantioselectivities (up to 85% ee) in the presence of the multifunctional HZNU-Phos with both a phosphine center and BINOL-based diol moiety that played a crucial role in the achievement of the best enantioselectivity for this reaction.

The first example of palladium-catalyzed chelation-assisted C-H olefination of 2-amino biaryls using readily available vinylsilanes as unactivated olefinating reagents has been developed, affording valuable arylated vinylsilane compounds in moderate to excellent yields and with exclusive (E)-selectivities.

The detailed procedure and mechanistic analysis for the synthesis of polymethylhydrosiloxane-based semi-interpenetrating networks (PMHS-SIPNs) with Si−H and other functional groups under mild reaction conditions was presented in this work. And the Si−H –containing organosilicon materials was proved to be a useful support in the construction of nanosilver catalyst according to the previous reported strategy that with the concept of titanium-promoted reduction of ester with hydrosilane for well-distributed dispersion of titanium and nanosilver on cross-linked PMHS-SIPNs supporter (Ag@TiO2@PMHSIPN). Furthermore, a highly efficient method for the synthesis of primary propargylic alcohols has been developed using PMHS-based semi-interpenetrating networks –supported nanosilver (Ag@TiO2@PMHSIPN) as catalyst.

An investigation on the structural, electronic, thermodynamic, and mechanical properties of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX)/2-methylpyridine-N-oxide (MPNO) cocrystal was carried out from 0 to 100 GPa by using a dispersion-corrected density functional theory (DFT-D) method. Our calculated crystal structure is in excellent agreement with experimental results at ambient pressure. Based on the analysis of lattice parameters, lattice angles, bond lengths, bond angles, and dihedral angles under high pressure, we observe that HMX molecules in the cocrystal bulk are seriously distorted but MPNO molecules remain relatively unchanged. Hydrogen bond lengths are greatly shortened under high pressure. In addition, with the increase in pressure, the bandgap decreases gradually. However, it increases suddenly at 70 GPa. Some important hydrogen bonds between HMX and MPNO are also observed in the density of states spectrum. According to the thermodynamic analysis, this cocrystal is more easi...

The palladium-catalyzed desymmetrization of silacyclobutanes using electron-deficient alkynes proceeds with high enantioselectivity in the presence of a chiral P ligand; this provides a facile approach for the synthesis of novel silicon-stereogenic silanes. In this work, we used hybrid density functional theory (DFT) to elucidate the mechanism of the palladium-catalyzed desymmetrization of silacyclobutanes with dimethyl acetylenedicarboxylate. Full catalytic cycle including two different initiation modes that were proposed to be a possible initial step to the formation of the 1-pallada-2-silacyclopentane/alkyne intermediate-the oxidative addition of the palladium complex to the silacyclobutane Si-C bond (cycle MA) or coordination of the Pd0 complex with the alkyne C≡C bond (cycle MB)-have been studied. It was found that the ring-expansion reaction began with cycle MB is energetically more favorable. The formation of a seven-membered metallocyclic PdII intermediate was found to be the rate-determining step, whereas the enantioselectivity-determining step, oxidative addition of silacyclobutane to the three-membered metallocyclic PdII intermediate, was found to be quite sensitive to the steric repulsion between the chiral ligand and silacyclobutane.

To shield light on the mechanism of palladium-catalyzed allylic substitutions with structurally diverse nucleophiles (up to 99% ee) in the presence of Fei-Phos ligand (chiral trans-1,2-diaminocyclohexane-derived biphosphine, CycloN2P2-Phos) as an effective chiral P-ligand, mechanistic studies were performed for clarification of the role of multifunctional Fei-Phos in this reaction. The cooperative action of nitrogen and phosphorous atoms in the present Pd-catalyzed allylic alkylation is proved to be a diphosphine-based catalyst system but not a nitrogen-controlled or monophosphine-involved transition state.

An enantioselective Pd-catalyzed silicon–carbon bond-forming silylation reaction of aryl iodides with hydrosilanes for the synthesis of silicon-stereogenic silanes has been developed, in which a systematic optimization of a TADDOL-derived monodentate phosphoramidite ligand set resulted in the identification of a new TADDOL-derived phosphoramidite ligand that accesses chiral silanes with moderate to good yield and enantioselectivity under mild conditions.

It was found that the tridentate O,N,O-type Schiff base ligand bearing suitable substituents was a highly effective promoter in the catalytic asymmetric bromochlorination reaction, in which the corresponding aromatic bromochloroalcohols with vicinal halogen-bearing stereocenters were formed with perfect regioselectivity, with moderate to excellent enantioselectivities (up to 93% ee), and with good yields and chemoselectivities.

It was found that the catalytic Huisgen cycloaddition reaction of succinimide-derived bisalkynes with azides resulted in useful succinimide-derived triazoles bearing quaternary carbon-stereogenic centers with good to excellent yields as well as good chemoselectivity and moderate to high enantioselectivities (up to 97% ee), in which the CuF2/Tao-Phos complex was proved to be an effective bimetallic catalyst in the presence of triethylamine. The mechanistic studies based on the effect of reaction parameters on stereoselectivity as well as ESI-MS analysis suggested that our ligand (Tao-Phos) and related binuclear copper centers play a crucial role in this asymmetric click chemistry because of the strong catalyst–substrate interaction with the aid of a possibly in situ formed binuclear or multinuclear copper-based transition state. This work not only provides a new example of a Cu(II)-mediated asymmetric AAC reaction involving chelating base and azides, but also suggests the significance of binuclear copper species in catalytic asymmetric click reactions with two copper center-involved enantioselective inductions.

A palladium-catalyzed ketoxime-chelation-assisted enantioselective C–H olefination of 2-arylcyclohex-2-enone oxime ether with a wide range of olefins as coupling partners was developed. Employing ketoxime ether as an efficient directing group, a variety of axially chiral vinyl arenes was synthesized by Pd(II)-catalyzed C–H functionalization with excellent enantioselectivities (96 → 99% ee) under mild conditions.

An enantioselective magnesium-catalyzed conjugate addition of trimethylsilyl cyanide to chalcones in the presence of Py-BINMOL with multiple stereogenic centers, through dual activation of substrates, has been successfully developed with moderate to good enantioselectivities and in good yields.

A multistereogenic salen–Mn(III) complex bearing an aromatic pocket and two benzylic groups as helping hands was found to be efficient in the catalysis of asymmetric cyanosilylation. The salen–Mn catalyst partially mimics the functions of biocatalysts by reasonably utilizing the steric and electronic properties of the catalytic center to interact with the substrate.

The use of ligands to tune the reactivity and regioselectivity of transition metal-based catalyst for silicon-mediated organic synthesis (SiMOS) is an important topic and challenge in organosilicon chemistry and synthetic organic chemitstry. In this manuscript, the dual ligand platinum catalyst system was developed for the hydrosilylation of alkynes. It was found that regioselectivity enhancement was determined with combinational use of phosphine ligand (6a) and multifunctional Py-BINMOL ligand (4a). The corresponding vinylsilanes were obtained in high yields and high regioselectivities.

The enantioselective construction of a family of chiral glycine-derived aldimino esters is described. The asymmetric tandem conjugate addition–elimination procedure is characterized by its exceptional mild reaction conditions and features with an exquisite enantioselectivity profile using commercially available silver/DTBM-SegPhos catalyst, allowing for the facile preparation of a variety of substituted and chiral glutamic acid derivatives (up to 99% ee) bearing Schiff base in a straightforward manner.

It was found that 1,2-trifluoromethylation reactions of ketones, enones, and aldehydes were easily accomplished using the Prakash reagent in the presence of catalytic amounts of cesium carbonate, which represents an experimentally convenient, atom-economic process for this anionic trifluoromethylation of non-enolisable aldehydes and ketones.

The catalytic cycles of palladium-catalyzed silylation of aryl iodides, which are initiated by oxidative addition of hydrosilane or aryl iodide through three different mechanisms characterized by intermediates R3 Si-PdII -H (Cycle A), Ar-PdII -I (Cycle B), and PdIV (Cycle C), have been explored in detail by hybrid DFT. Calculations suggest that the chemical selectivity and reactivity of the reaction depend on the ligation state of the catalyst and specific reaction conditions, including feeding order of substrates and the presence of base. For less bulky biligated catalyst, Cycle C is energetically favored over Cycle A, through which the silylation process is slightly favored over the reduction process. Interestingly, for bulky monoligated catalyst, Cycle B is energetically more favored over generally accepted Cycle A, in which the silylation channel is slightly disfavored in comparison to that of the reduction channel. Moreover, the inclusion of base in this channel allows the silylated product become dominant. These findings offer a good explanation for the complex experimental observations. Designing a reaction process that allows the oxidative addition of palladium(0) complex to aryl iodide to occur prior to that with hydrosilane is thus suggested to improve the reactivity and chemoselectivity for the silylated product by encouraging the catalytic cycle to proceed through Cycles B (monoligated Pd0 catalyst) or C (biligated Pd0 catalyst), instead of Cycle A.

A palladium-catalyzed allylic alkylation of unsubstituted 2-cyanoacetates using a 1,1′-bi-2-naphthol-derived multifunctional N,O,P ligand is reported. A number of chiral monosubstituted 2-cyanoacetates with two adjacent stereogenic carbon centers are obtained in this Pd-catalyzed asymmetric allylic alkylation reaction, in which the multistereogenic and multifunctional 1,1′-bi-2-naphthol-derived N,O,P ligand-promoted Pd-catalyzed asymmetric allylic alkylation reaction proceeds smoothly in high diastereo- and enantioselectivity (up to >99:1 dr and up to 96 % ee).

It was found that the cinchona-derived primary amines and their combined catalyst systems with chiral organic acid or Lewis acid have been successfully applied in the cross-aldol reaction of trifluoromethyl ketones and aliphatic ketones. Excellent yields and good enantioselectivities (up to 89% ee) of the resulting β-trifluoromethyl-β-hydroxy ketones were obtained in the chiral primary amine catalyzed cross-aldol reaction under different conditions, which also led to both enantiomers of the desired products. This study also demonstrated the importance of synergistic effect of chiral organic acid on the primary amine catalysis.

A facile protocol is developed for the synthesis of dibenzophosphole oxides through palladium-catalyzed direct arylation reaction of readily available ortho-halodiarylphosphine oxides.

Direct functionalization of terpyridines is an increasingly important topic in the field of dyes and catalysis as well as supramolecular chemistry, but its synthesis and transformation is usually challenging. Herein, a HOMO-raising strategy is reported for the construction of a super-stable novel terpyridine chromophores, in which the selective oxidation of terpyridines at its 3-position was determined successfully to the synthesis of phenol-functionalization of terpyridines (TPyOHs) bearing a hydrogen bonding group. The corresponding TPyOHs displayed strong aggregation-induced emission and exhibited highly selective and visual detection of Zn

Facile carbocation-initiated [4+2] cycloaddition of o-anisole-substituted propargyl silyl ethers and ynamides led to the formation of 4-vinylcoumarins. Subsequent intramolecular cyclization of 3-aryl-4-vinylcoumarins afforded polycyclic coumarin derivatives 11,12-dihydronaphtho[1,2-c]chromen-5-ones in excellent yields under mild photo-irradiated conditions established by fluorescence analysis-oriented screening.

A novel synthesis of N-sulfonylamidines by catalyst-free hydroamination of N,N-disulfonyl ynamides with amines was developed. Alkyl amines react with N,N-disulfonyl ynamides under mild conditions, whereas aryl amines require higher temperatures. Plausible mechanisms are proposed to explain this reaction.

A facile synthesis of 3-substituted 2-amidobenzofurans and 2-amidobenzothiophenes via electrophilic cyclization reaction of o-anisole- and o-thioanisole-substituted ynamides with I2, NBS and NCS was developed. The products 3-iodo-2-amidobenzofurans were further transferred into 3-aryl-, 3-alkynyl, and 3-vinyl-2-amidobenzofurans via Pd-catalyzed reactions such as Suzuki–Miyaura and Sonogashira cross-coupling reactions and the Heck reaction.

A facile carbocation-induced electrophilic cyclization reaction has been developed for the synthesis of 3-alkyl- or 3-allenyl-2-amidobenzofurans from o-anisole-substituted ynamides and diarylmethanol or 1,1-diarylprop-2-yn-1-ol.

The mechanism-oriented reaction design for the divergent synthesis of chiral molecules from simple starting materials is highly desirable. In this work, aromatic amide-derived nonbiarylatropisomer/silver (silver/Xing-Phos) complex was used to catalyze the Michael addition of glycine aldimino esters to chalcones and successfully applied to the subsequent cyclocondensation to afford substituted cis-Δ(1)-pyrroline derivatives with up to 98 % ee. Besides the inherent performance of the chiral Ag/Xing-Phos catalyst system, it was found that the workup of such reactions played an important role for the stereoselective construction of stereodivergent Δ(1)-pyrrolines, in which an epimerization of the cis-Δ(1)-pyrrolines to the trans-isomers during was revealed.

It was found that the catalytic Huisgen cycloaddition reaction of succinimide-derived bisalkynes with azides resulted in useful succinimide-derived triazoles bearing quaternary carbon-stereogenic centers with good to excellent yields as well as good chemoselectivity and moderate to high enantioselectivities (up to 97% ee), in which the CuF2/Tao-Phos complex was proved to be an effective bimetallic catalyst in the presence of triethylamine. The mechanistic studies based on the effect of reaction parameters on stereoselectivity as well as ESI-MS analysis suggested that our ligand (Tao-Phos) and related binuclear copper centers play a crucial role in this asymmetric click chemistry because of the strong catalyst–substrate interaction with the aid of a possibly in situ formed binuclear or multinuclear copper-based transition state. This work not only provides a new example of a Cu(II)-mediated asymmetric AAC reaction involving chelating base and azides, but also suggests the significance of binuclear copper species in catalytic asymmetric click reactions with two copper center-involved enantioselective inductions.