Total Synthesis of Terpioside B

The first total synthesis of terpioside B (1) has been accomplished. Key steps include the stereoselective installments of a set of challenging 1,2-cis-glycosidic linkages. Thus, alpha(1,4)-linkedd-galactoside was effectively constructed from a 1,2-anhydrogalactose donor and an unprotected 1,6-anhydrogalactose acceptor by using a boron-mediated aglycon delivery (BMAD) method. In addition, alpha-l-fucofuranosides were stereoselectively and simultaneously constructed by remote group-assisted 1,2-cis-alpha-stereoselective glycosylations.