Stereoselective Synthesis of β-glycosyl Esters via 1-Hydroxybenzotriazole Mediated Acylation of Glycosyl Hemiacetals.

Highly stereoselective access to β-glycosyl esters was disclosed, employing 1-hydroxybenzotriazole (HOBt) mediated esterification of glycosyl hemiacetals in the presence of EDCI and 1,4-diazabicyclo[2.2.2]octane (DABCO). Mechanistic studies indicated a dynamic kinetic acylation pathway. In addition, a stereoretentive esterification of glycosyl hemiacetals with tert -butyloxycarbonyl ortho -hexynylbenzoate and DMAP was also reported.