A Highly Convergent Total Synthesis of (+)-Myxovirescine M2. Preliminary Communication

The antibiotic myxovirescine M₂ was synthesized from seven building blocks ( 1 – 7 , Scheme 1), with the following chiral starting materials being employed: (S)-malic acid, (+)-D -ribonolactone, (S)-2-(hydroxymethyl)butanoate, and (2R,4S)-5-hydroxy-2,4-dimethylpenLanoate. Three new nucleophilic reagents, 8 – 10 , for C-C bond formation have been used. The key steps of the synthesis are: a Suzuki coupling between an alkyl borane and a vinyl bromide ( 4 + 12e → 13 ), a Julia olefinalion ( 14 + 17 → 18 ), and a Yamaguchi macrolactonizalion to form the 28-membered lactone ( 18 → 19 ), This extremely convergenl synthetic approach will allow the preparation of a number of the 31 known myxovirescine molecules.