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.
Jacobi, P. A., Brielmann, H. L., & Hauck, S. I. (1995). Synthesis of cyclic enamides by intramolecular cyclization of acetylenic amides. Tetrahedron Letters, 36(8), 1193–1196. https://doi.org/10.1016/0040-4039(95)00031-7