Studies directed toward the synthesis of the massileunicellins. Part 2

The fully substituted hydroisobenzofuran core of the massileunicellins containing eight contiguous stereocenters was prepared in 12 steps from (S)-(+)-carvone. Noteworthy elements of the synthesis include a one-step oxidative rearrangement/epoxidation, a novel stereoselective directed reduction of a keto diol, and a directed hydrogenation of a congested tetrasubstituted alkene.