Stereoselective synthesis of 1,2-trans-β-glycosyl esters from glycosyl chlorides via phase-transfer catalysis.

An efficient and highly stereoselective synthesis of β-glycosyl esters has been developed using perbenzylated glycosyl chlorides under tetrabutylammonium chloride (TBAC)-catalyzed phase-transfer conditions. This approach demonstrates broad applicability across a variety of carboxylic acids and glycosyl donors, showcasing excellent substrate generality. Conducted under mild conditions (60 °C, catalytic TBAC loading), the reaction affords the desired glycosyl esters in good to excellent yields. All products were obtained as a single stereoisomer, attesting to the exceptional stereoselectivity of the method. This work establishes a reliable and practical avenue for the stereoselective preparation of natural-product-like glycosyl esters.