Stereoselective synthesis of protected - and -dideoxysugars and analogues Prins cyclisations

A de novo approach for the rapid construction of orthogonally protected l - and d -deoxysugars and analogues is described. A novel and robust silicon-acetal undergoes Prins cyclisations with a series of homoallylic alcohols in high yield and excellent stereocontrol. Modified Tamao-Fleming oxidation of the resulting silyltetrahydropyrans gives direct access to deoxyglycoside analogues and the approach was showcased in the synthesis of protected l -oliose, a component of the anticancer agent aclacinomycin A. Cyclisation of a silicon acetal with homoallylic alcohols to generate silyltetrahydropyrans and subsequent oxidation gives rapid access to deoxyglycoside analogues.