Synthesis of cyclic enamides by intramolecular cyclization of acetylenic amides

Abstract

Cyclic enamides 12 of a type useful in the synthesis of naturally occurring chlorins, isobacteriochlorins, and corrins have been prepared by a process involving Nicholas-Schreiber condensation to afford acetylenic amides 13, followed by either n-Bu4NF or LiA1(NHBn)4-catalyzed ring closure. © 1995.