A carbonylative cross-coupling strategy to the total synthesis of the sarcodictyins: preliminary studies and synthesis of a cyclization precursor

Preliminary studies were conducted on the implementation of a new strategy to the total synthesis of the common diterpenoid tricyclic skeleton of sarcodictyins and eleutherobin. According to the approach presented, a key retrosynthetic disconnection is devised at the C3–C5 position, identifying a carbonylative cross-coupling reaction as the medium-sized ring forming step. The synthesis of a fully functionalized cyclization precursor, comprising a Z vinylstannane and a carboalkoxy-substituted Z enol triflate as reactive centres, is described.