Formation of heterocycles by the Mitsunobu reaction. Stereoselective synthesis of (+)-α-skytanthine

Cyanomethylenetributylphosphorane was shown to mediate the dehydrocyclization of diols and amino alcohols to give the corresponding 6-membered O- and N-heterocycles in 90% or better yields. Using the reaction as a key step, (+)-α-skytanthine, a unique mono terpene alkaloid, was synthesized stereoselectively.