Yan-Kai Liu

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A highly stereoselective tandem Michael addition-Wittig reaction of (3-carboxy-2-oxopropylidene)triphenylphosphorane and alpha,beta-unsaturated aldehydes has been developed by employing the combined catalysis of a newly designed bulky chiral secondary amine 1g, LiClO(4), and DABCO. The multifunctional 6-carboxycyclohex-2-en-1-ones were generally obtained in(More)
We successfully expand the application of lactols or cyclic hemiaminals as nucleophiles for the asymmetric synthesis of both N,O- and N,N-acetal moieties contained in the structure of ring-fused piperidine derivatives. This efficient one-pot protocol involves an organocatalyzed asymmetric aza-Diels-Alder reaction and iminium ion induced cyclization sequence(More)
Based on the appropriate choice of electrophiles, one-pot, multicomponent, enantioselective domino reactions have been realized which contain a five-step sequence and provide highly efficient access to potentially bioactive chroman-2-one derivatives as a single diastereoisomer with excellent enantioselectivities and in high yields. This new strategy could(More)
A new, general, and practical procedure for the highly enantioselective synthesis of functionalized nitrogen-containing heterocycles has been developed. The simple cyclic hemiaminals were directly catalyzed for the first time as nucleophiles in an enamine-based asymmetric conjugate addition reaction. The practical approach recycles the catalyst and solvent(More)
An open-close strategy in asymmetric catalysis is newly developed. With this powerful strategy, lactols are directly applied as potential precursors of lactones in enamine-based asymmetric Michael reactions providing a facile access to α-functionalized lactones containing two adjacent stereogenic centers as a single diastereomer in good to excellent yields(More)
An asymmetric aldol-desymmetrization sequence was developed which provided highly efficient access to important bicyclic oxygen-containing scaffolds with multiple chiral centers and one is a quaternary stereogenic center containing a free hydroxy group. Moreover, starting from racemic precursors, the final products were obtained as two separable(More)
The asymmetric organocatalyzed diversity-oriented one-pot synthesis has been developed to construct chroman-2-one derivatives and other heterocyclic compounds with excellent efficiency and stereoselectivity. The reactions represent a challenging issue, since it altered the inherent selectivity profiles exhibited by the substrates of 2-hydroxycinnamaldehyde(More)
[reaction: see text] The chemoselective ring opening of N-tosyl aziridines with aldehydes catalyzed by an N-heterocyclic carbene was investigated under aerobic conditions. Unexpected carboxylates of 1,2-amino alcohols from the corresponding aldehydes, rather than the acyl anion ring-opened beta-amino ketones, were exclusively obtained. A plausible mechanism(More)
Lactols and cyclic hemiaminals were directly used in a one-pot organo/organo dual catalytic system induced [2+2+2] tandem reaction for the asymmetric construction of six-membered carbocycles. The enamine-based stereoselective Michael addition of lactols or cyclic hemiaminals to electron-deficient olefinic oxindole motifs provided chiral C4 components, which(More)