De novo asymmetric synthesis of an alpha-6-deoxyaltropyranoside as well as its 2-/3-deoxy and 2,3-dideoxy congeners.

A highly divergent de novo asymmetric synthesis of benzyl alpha-6-deoxyaltropyranoside, benzyl alpha-ascarylopyranoside, benzyl alpha-amicetopyranoside, and benzyl alpha-digitoxopyranoside has been achieved via a common pyranone intermediate. The routes rely upon a palladium(0)-catalyzed glycosylation reaction and corresponding post-glycosylation transformations. The control of the absolute and relative stereochemical configuration came from a Noyori reduction of 2-acylfuran and subsequent diastereoselective introduction of other stereogenic centers.