A samarium-mediated Barbier reaction was performed to a€ord N-acetylneuraminic acid -Cglycosyl compounds (`` -C-glycosides'') in excellent yield. The neuraminic acid phenyl sulfone or 2-pyridyl sulfone derivatives reacted with ketones or aldehydes resulting in the instantaneous and stereospeci®c formation of Neu5Ac -C-glycosides. The phenyl and the 2-pyridyl sulfone derivatives were equally e€e...

a series of hydroxysemicarbazone derivatives of substituted diaryl ketones and acetophenones were synthesized and their structures were confirmed by analytical and spectroscopic methods including elemental analysis, infrared and nuclear magnetic resonance spectroscopy. the derivatives were prepared by a condensation reaction between n-hydroxysemicarbazide and substituted diaryl ketones or aceto...

Techniques for the preparation of a-lithio selenoxides have been developed. These reagents react cleanly with most aldehydes and ketones to give 0-hydroxy selenoxides, which can be thermolyzed to allyl alcohols or reduced to &hydroxy selenides, The P-hydroxy selenides are further transformed to olefins by reductive elimination. a-Lithio selenoxides can also be alkylated and acylated, although t...

Catalytic asymmetric Corey-Chaykovsky epoxidation of various ketones with dimethyloxosulfonium methylide using a heterobimetallic La-Li(3)-BINOL complex (LLB) is described. The reaction proceeded smoothly at room temperature in the presence of achiral phosphine oxide additives, and 2,2-disubstituted terminal epoxides were obtained in high enantioselectivity (97%-91% ee) and yield ( > 99%-88%) f...