The total synthesis of moenomycin A.

Moenomycin A is the only known natural antibiotic that inhibits bacterial cell wall synthesis by binding to the transglycosylases that catalyze formation of the carbohydrate chains of peptidoglycan. We report here the total synthesis of moenomycin A using the sulfoxide glycosylation method. A newly discovered byproduct of sulfoxide reactions was isolated that resulted in substantial loss of the glycosyl acceptor. A general method to suppress this byproduct was introduced, which enabled the glycosylations to proceed efficiently. The inverse addition protocol for sulfoxide glycosylations also proved essential in constructing some of the glycosidic linkages. The synthetic route is flexible and will allow for derivatives to be constructed to further analyze moenomycin A's mechanism of action.