Li-Jun Xia

Desymmetric ring-opening of meso-epoxides with anilines: a simple way to chiral β-amino alcohols

Abstract Chiral β-amino alcohols were afforded by desymmetric ring-opening of meso -epoxides with anilines catalyzed by chiral Yb triflate complex in up to 80.1% ee.

Efficient Suzuki‐Type Cross‐Coupling of Enantiomerically Pure Cyclopropylboronic Acids

Optically active cyclopropanes (e.g. 1) can be prepared by the use of tartaric acid derivatives as chiral auxiliaries in the palladium-catalyzed cross-coupling of optically active cyclopropylboronic acids with electrophiles. The absolute configuration of the chiral carbon atom is retained, and the reaction proceeds with good yields and enantiomeric excesses. R=H, p-Ph, o-CO2 CH3 , p-CO2 CH3 , p-NO2 , o-OCH3 , m-OCH3 .

Enantioselective ring opening of meso-epoxides with thiols catalyzed by a chiral (salen)Ti(IV) complex

Abstract A chiral (salen)Ti(IV) complex was an efficient catalyst in the asymmetric ring opening of meso -epoxides 1 with thiols 2 in high yields and good ee.

Asymmetric hetero-Diels–Alder reaction of 1-alkyl-3-silyloxy-1,3-dienes with ethyl glyoxylate catalyzed by a chiral (salen)cobalt(II) complex

Abstract The hetero-Diels–Alder reactions of 1-alkyl-3-( tert -butyldimethylsilyl)oxy-1,3-butadienes with ethyl glyoxylate catalyzed by chiral salen–metal complexes have been studied. With a cobalt(II) complex as the catalyst, the reaction of 1-(2-benzyloxyethyl)-3-( tert -butyldimethylsilyl)oxy-1,3-butadiene with ethyl glyoxylate gave the Diels–Alder product in 75% isolated yield with the endo : exo ratio >99:1 and the enantiomeric excess ≥52%. The effects of temperature, catalyst and solvent are also discussed.

Base‐catalyzed epimerization of the butenolide in annonaceous acetogenins

The elusive epimerization process in the chiral butenolide moiety of Annonaceous acetogenins was examined under several sets of conditions commonly used for elimination leading to the alpha, beta-unsaturated lactone and the results provide practical guidance in choosing elimination conditions.

Synthesis of a key intermediate for corossolin using hydrolytic kinetic resolution of epoxides

A convergent synthesis of the key intermediate for corossolin has been achieved using hydrolytic resolution of epoxides as the key step, which extends the scope of the applicable substrates for hydrolytic kinetic resolution to cover multifunctionalized large molecules.

Asymmetric synthesis of (2R,3S)-2,3-epoxyamides via camphor-derived sulfonium ylides

Enantiomerically enriched trans-2,3-epoxyamides 3 were prepared by the reaction of aldehydes 2 with camphor-derived chiral sulfonium ylide 1 in good yields and moderate to good ee values. The absolute configuration of the reaction product is also determined by chemical transformations.