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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 PdII‐catalyzed carbopalladation‐initiated cascade reactions still remains a formidable challenge. Herein, an unprecedent enantioselective [3+2] annulation of oxime ethers and alkynes has been developed, providing both spiro and nonspiro indenes bearing all‐carbon quaternary stereocenters in good yields (up to 98 %) with excellent enantioselectivities (up to >99 % ee). This annulation is accomplished by merging the PdII‐catalyzed atroposelective C−H activation/double carbopalladation and the transient axial‐to‐central chirality transfer process, constituting the first successful example of catalytic chirality transfer strategy involving axially chiral styrene intermediate. [ABSTRACT FROM AUTHOR]

Hydrosilylation of unsaturated carbon-carbon bonds with hydrosilanes is a very important process to access organosilicon compounds and ranks as one of the most fundamental reactions in organic chemistry. However, catalytic asymmetric hydrosilylation of activated alkenes and internal alkenes has proven elusive, due to competing reduction of carbon-carbon double bond or isomerization processes. Herein, we report a highly enantioselective Si-C coupling by hydrosilylation of carbonyl-activated alkenes using a palladium catalyst with a chiral TADDOL-derived phosphoramidite ligand, which inhibits O-hydrosilylation/olefin reduction. The stereospecific Si-C coupling/hydrosilylation of maleimides affords a series of silyl succinimides with up to 99% yield, >99:1 diastereoselectivity and >99:1 enantioselectivity. The high degree of stereoselectivity exerts remote control of axial chirality, leading to functionalized, axially chiral succinimides which are versatile building blocks. The product utility is highlighted by the enantioselective construction of N-heterocycles bearing up to three stereocenters. Catalytic asymmetric hydrosilylation of internal alkenes has proven elusive due to more favourable double bond reduction or isomerization. Here, the authors show an enantioselective Si-C coupling by hydrosilylation of activated alkenes using a palladium/phosphoramidite catalyst affording axially chiral succinimides. [ABSTRACT FROM AUTHOR]

In the past years, stereoselective functionalizations of hydroxyl groups of alcohol substrates with chlorosilanes leading to silyl ether formation have evolved from a functional-group protection to an enantioselective synthetic strategy. This work comprises a controlled desymmetrization of dichlorosilanes by using a family of structurally specific chiral diols, chiral 1,1′-binaphthalene-2-α-arylmethanol-2′-ol (Ar-BINMOL). This process led to the facile construction of silicon-stereogenic organosilicon compounds with high yields and good diastereoselectivities. In addition, the diasteroselective silylation of chiral diols might not only be of interest for the development of highly stereoselective nucleophilic silylation, but also shed light on the construction of novel chiral phosphine ligands bearing a silicon-stereogenic center. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Recently, academic chemists have renewed their interest in the development of 1,1′-binaphthalene-2,2′-diol ( BINOL)-derived chiral ligands. Six years ago, a working hypothesis, that the chirality matching of hybrid chirality on a ligand could probably lead to high levels of stereoselective induction, prompted us to use the axial chirality of BINOL derivatives to generate new stereogenic centers within the same molecule with high stereoselectivity, obtaining as a result sterically favorable ligands for applications in asymmetric catalysis. This Personal Account describes our laboratory's efforts toward the development of a novel class of BINOL-derived atropisomers bearing both axial and sp3 central chirality, the so-called Ar- BINMOLs, for asymmetric synthesis. Furthermore, on the basis of the successful application of Ar- BINMOLs and their derivatives in asymmetric catalysis, the search for highly efficient and enantioselective processes also compelled us to give special attention to the BINOL-derived multifunctional ligands with multiple stereogenic centers for use in catalytic asymmetric reactions. [ABSTRACT FROM AUTHOR]

An interesting group of multifunctional phosphines (Ar-BINMOL-Phos; Ar-BINMOL=1,1′-binaphthalene-2-α-arylmethanol-2′-ol) with multi-stereogenic centers of axial and sp3-central chirality has been prepared successfully from a single chiral source through a concise synthetic route, in which the neighbouring lithium-promoted [1,2]-Wittig rearrangement proceeding with excellent diastereoselectivity and enantioselectivity is the key process in this approach. Also, in the catalytic alkynylation of aromatic aldehydes with terminal alkynes, the combination of these Ar-BINMOL-Phos ligands with dimethylzinc was found to be an effective catalyst system to afford predominantly the S-configured propargylic alcohols, whereas the additional use of calcium hydride and n-butyllithium along with the same Ar-BINMOL-Phos ligands gave the R-configured products in high yields and excellent enantioselectivities (up to >99% ee). [ABSTRACT FROM AUTHOR]

The fluorination reaction is an important organic transformation for asymmetric synthesis. In this article, we reported the determination of chiral primary amine–based multicatalyst systems for enantioselective fluorination of β-ketoester. Studies on the enantioselective organocatalytic fluorination promoted by cinchona alkaloid–derived chiral primary amines in the absence of various co catalysts revealed that the combined metal salts and organocatalysts resulted in poor conversion and enantioselectivities, whereas the combinational use of L-leucine and QN-NH2as dual primary amine catalysts led to the determination of a novel dual organocatalyst with promising catalytic activity. On the basis of these results, we revealed that the steric environment of the chiral enamine intermediate formed by the condensation of β-ketoester with the chiral primary amine is most responsible for the observed enantioselectivity. [Supplementary materials are available for this article. Go to the publisher's online edition ofSynthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.] [ABSTRACT FROM AUTHOR]

A series of silicon-containing diols are synthesized and used in lipase-catalyzed remote desymmetrization. This synthetic method is valuable in the construction of optically active silicon-stereogenic organosilicon compounds. Good enantioselectivities of the remote desymmetrization was achieved with Candida antarctica lipase B (CAL-B) (up to 90:10 er). [ABSTRACT FROM AUTHOR]

The synthesis of silicon-stereogenic silanes is undoubtedly one of the most intriguing and challenging aspects in organic chemistry and organosilicon chemistry and is neglected by chemists to some extent. This critical reviewwill focus on the recent exciting advances in the synthesis of silicon-stereogenic silane and outline the application of these chiral silanes in asymmetric synthesis (89 references). [ABSTRACT FROM AUTHOR]

In the past few years, primary amine catalysts derived from natural amino acids, Cinchonaalkaloids and other chiral amines have emerged as readily available, highly versatile and extremely powerful catalysts in asymmetric synthesis. They have been demonstrated to be effective catalysts in a wide range of enantioselective organic reactions. In comparison with secondary amine-mediated transformations, the use of primary amine organocatalysts has often been shown to be complementary or superior. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Abstract: A straightforward and practical method for the direct fluorination and chlorination of various β-ketoesters employing a phase-transfer catalyst is developed. The desired products with fluorine/chlorine-substituted quaternary chiral centers are prepared with good to excellent enantioselectivities. [Copyright &y& Elsevier]

Simple modifications of our novel ligand (Xing-Phos) were presented in this work, and a series of aromatic tertiary amide derived non-biaryl atropisomers were successfully synthesized in good yields. In addition, it was found that the multifunctional aromatic tertiary amide derived non-biaryl atropisomers exhibited an excellent endo -selectivity in the silver-catalyzed [3+2]-cycloaddition of azomethine ylides with N -aromatic maleimide. And especially, good to high levels of enantioselectivity (up to 98% ee ) was obtained with a wide range of substrates in the presence of syn -( R , R S )- 2a (Xing-Phos). Furthermore, on the basis of the experimental data, it was demonstrated that a trace amount of water play an important role in the enhancement of enantioselectivity. [ABSTRACT FROM AUTHOR]

Abstract: A new family of C 2-axially chiral monophosphines (Ar-NNPs) from Ar-BINMOLs was developed for silver-catalyzed asymmetric vinylogous Mannich reaction of (furan-2-yloxy)trimethylsilane with aromatic aldimines. It was found that the enantioselective vinylogous Mannich-type reactions of trimethylsiloxyfuran with aldimines are catalyzed efficiently by silver(I) complexes of the Ar-BINMOL-derived chiral monophosphine. This procedure displays wide aldimine versatility, excellent yields (up to 99% isolated yields), moderate to good enantioselectivity (up to 78%ee) and exceptional diastereoselectivity (>99:1 dr) in most cases examined. The molecular structure of silver–monophosphine complex was confirmed by X-ray analysis and revealed that the benzyl group on chiral monophosphine provided dual function with weak silver–π/π–π stacking and steric repulsion to favour the diastereoselective Re-nucleophilic addition of siloxyfuran to imine. [Copyright &y& Elsevier]

Abstract: It was found that the chiral salan compound derived from chiral Ar-BINMOL could serve as a fluorescent turn-on sensor for CuCl salt and the corresponding salan–copper(II) complex can work as a fluorescent sensor for the selective recognition and discrimination of protected α-amino acids with considerable selectivity. [Copyright &y& Elsevier]

Abstract: The LBAs (Lewis acid-assisted Brønsted acid catalysis) is proposed as possible mechanistic process in the simple FeCl3-catalyzed Michael reactions of chalcones with active methylene compounds in organic solvents. And iron salts were found to be effective promoters in the asymmetric Michael addition of 4-hydroxycoumarin to α,β-unsaturated ketone, which resulted in excellent yield and high level of enantioselectivity (up to 91% ee) in the presence of low catalytic amount of iron and simple chiral primary amine. [Copyright &y& Elsevier]

Combination of a cinchona alkaloid-derived primary amine with L-leucine gives a dual amine system with promising catalytic activity in enantioselective fluorination reactions of indanone-2-carboxylates (I). [ABSTRACT FROM AUTHOR]