Boron-mediated aglycon delivery (BMAD) for the stereoselective synthesis of 1,2-cis glycosides.

1,2-cis Glycosides are frequently found in biologically active natural products, pharmaceutical compounds, and highly functional materials. Therefore, elucidating the role of mechanism of their biological activities will help clarify the structure-activity relationships of these diverse compounds and create new lead compounds for pharmaceuticals by modifying their structures. However, unlike 1,2-trans glycosides, the stereoselective synthesis of 1,2-cis glycosides remains difficult due to the nonavailability of neighboring group participation from the 2-O-acyl functionalities of the glycosyl donors. In this context, we recently developed organoboron-catalyzed 1,2-cis-stereoselecitve glycosylations, called boron-mediated aglycon delivery (BMAD) methods. In this review article, we introduce the BMAD methods and several examples of their application to the synthesis of biologically active glycosides.