The Synthesis of Naturally Occurring ()‐Calyculin A

Abstract

Several intriguing transformations culminated in the first total synthesis of the title compound 1—the nonnatural ent-1 had been published previously—on coupling the fragments A, A′, B, and C. Crucial steps of the synthesis are the aldol reactions in the construction of fragment B, which solved the tricky problem of the stereoselective coupling of chiral fragments.