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, α(1,4)‐linked d‐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, α‐l‐fucofuranosides were stereoselectively and simultaneously constructed by remote group‐assisted 1,2‐cis‐α‐stereoselective glycosylations. Glycosphingilipids: Total synthesis of a natural glycosphingolipid possessing an l‐fucofuranoside residue is described (see figure). The synthetic strategy involves three types of glycosylations: i) boronic acid‐catalyzed regio‐ and 1,2‐cis‐α‐stereoselective glycosylation, ii) remote group‐assisted 1,2‐cis‐α‐stereoselective glycosylation, and iii) neighboring‐group‐assisted 1,2‐trans‐β‐stereoselective glycosylation.