Benzyl 2,3,6,2′,3′,6′-Hexa-O-Benzyl-β-Cellobioside

The title compound 3 (see opening scheme of this chapter) is an important intermediate in the preparation of C-4′ modi¥ed derivatives of lactose and cellobiose. The previously reported synthesis1 of 3 (Scheme 24.1) involved a sequence of reactions, developed originally by Hess et al.2 and Lipták et al.3 which started from cellobiose and led to benzyl glycoside 8. After per-O-benzylation (8 → 2B), reductive opening of the benzylidene ring in 2B gave 3 in an overall yield of ∼20%. Taking into consideration improvements made later by Edwards et al.4 and Twaddle et al.5 on various aspects of the sequence from 5 to 8, the overall yield of 3 could theoretically increase to ∼28%.