Organosilanes in synthesis: Application to an enantioselective svnthesis of methyl-L-callipeltose

[GRAPHIC] Methyl-L-callipeltose, the carbohydrate associated with callipeltoside A, has been synthesized in eight steps and 23% overall yield from enantioenriched allylsilane 6 and acetaldehyde. The key steps are a highly diastereoselective formal [4 + 2] annulation and a Cr(Vi)-catalyzed oxidative C-C bond cleavage to produce lactone 11.