First Total Synthesis of 1-<i>O</i>-β-d-Glucopyranosyl-5-deoxyadenophorine and Its Aglycon Congener: Determination of the Absolute Configuration

The first total synthesis of the potent glycosidase inhibitors 1-O-β-d-glucopyranosyl-5-deoxyadenophorine and its aglycon congener is described in respectively 13 steps (9% overall yield) and 9 steps (29% overall yield) from (R)-Garner aldehyde. The synthesis takes advantage of several key reactions including a diastereoselective allylation of a chiral imine, a stereoselective epoxidation, and a glycoside coupling. In addition this study established unambiguously the absolute configuration of the natural products.