Total synthesis of mycalamide A.

This communication describes a concise and efficient total synthesis of mycalamide A by the convergent coupling of pederic acid unit with the mycalamine unit. The left-half, (+)-7-benzoylpederic acid, was synthesized from (2R,3R)-3-methylpent-4-en-2-ol in seven steps and 34.6% overall yield through a route that features a one-step Pd(II)-catalyzed tandem Wacker/Heck cyclization reaction to prepare the tetrahydropyran ring system. The right-half, the mycalamine unit, was synthesized in 21 steps and 10.5% overall yield from diethyl d-tartrate. Effective, stereoselective methods were developed for the assembly of the two parts to yield either mycalamide A or C(10)-epi-mycalamide A.