An unprecedented enantioselective allylic alkylation of readily available aldimine esters has been developed, and is catalyzed by a synergistic Cu/Pd catalyst system. This strategy provides facile access to nonproteinogenic α,α-disubstituted α-amino acids in high yield with excellent enantioselectivity. The more challenging double allylic alkylation of glycinate-derived imine esters was also realized. Furthermore, this methodology was applied for the construction of the key intermediate of PLG peptidomimetics.

An unprecedented radical cross‐coupling reaction was achieved between glycine esters and racemic α‐bromoketones catalyzed by synergistic Brønsted acid/photoredox catalysis, thus serving as an efficient platform for the synthesis of highly valuable enantioenriched unnatural α‐amino acid derivatives. This dual catalysis provides a powerful capability to control the reactive radical intermediate and iminium ion, thereby enabling enantioconvergent bond‐formation in a highly stereochemical manner. An array of valuable enantioenriched unnatural α‐amino acid derivatives bearing two contiguous stereogenic centers are readily accessible with high diastereoselectivity and excellent enantioselectivity, which include α‐amino acids with a unique β‐fluorinated quaternary stereocenter or its β‐all‐carbon counterpart. A strong chiral amplification effect was observed in this dual catalytic system.

Herein, a novel strategy for the catalytic asymmetric synthesis of enantioenriched 3-cis- and 3-trans-substituted prolines has been successfully established via an unprecedented cascade radical addition/cyclization enabled by synergistic photoredox/Brønsted acid catalysis and subsequent base-assisted epimerization. The current protocol provides a unique de novo access to all four stereoisomers of 3-substituted prolines which are not readily achieved via currently established methods. This methodology could be further extended to the asymmetric synthesis of the full complement of stereoisomers of 3-substituted pipecolinic acids.

An unprecedented Pd-catalyzed asymmetric allylic alkylation of 1-(indol-2-yl)cyclobutanols followed by an -iminol rearrangement was reported. High yields with excellent chemo-, regio-, diastereo-, and enantioselectivities have been realized, affording a wide range of enantioenriched 2-spirocyclic-indolines bearing two contiguous stereocenters. The facial-selectivity of the ensuing rearrangement is controlled by the subtle difference of the substituents on the formed all-carbon quaternary stereogenic center in the allylic alkylation step. Non-activated racemic terminal allylic alcohols were utilized as efficient electrophiles via kinetic resolution pathway for the first time in Pd-catalyzed asymmetric allylic alkylation.The roles of Et 3 B additive are pivotal to activating allylic alcohols towards the formation of allylpalladium species and suppressing N/O allylic alkylation of indole with enhanced C3-nucleophilicity. ESI-HRMS experiments provided strong evidence for the existence of the key nucleophilic boron anionic species, which fully accounts for the essential roles of Et 3 B additive. Mechanism study indicates that the real catalytically active species is an electronic -cinnamyl-palladium complex coordinated by two phosphoramidite ligands, which is consistent with the observed non-linear effect and control experiments, and further confirmed by X-ray structure analysis.

The first example of highly efficient kinetic resolution of exo-3-oxodicyclopentadienes and endo-3-oxodicyclopentadiene has been developed by means of Cu­(I)-catalyzed asymmetric 1,3-dipolar cycloaddition of azomethine ylide. Compared with the existing methodologies for those synthetically important optically active convex molecules, the current protocol provides an alternative but more practical approach from the readily available racemic starting materials, which is free from the repetitive reduction/oxidation steps in the enzymatic resolution or the indispensable stoichiometric amount of chirality-induction reagents.