Synthesis of Cyclic Enamides by Intramolecular Cyclization of Acetylenic Amides.

Article abstract of DOI:10.1016/0040-4039(95)00031-7

Cyclic enamides 12 of a type useful in the synthesis of naturally occuring 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