Synthesis of Chromenopyrroles (Azacoumestans) from Functionalized Enones and Alkyl Isocyanoacetates

Org Lett. 2023 Jul 21;25(28):5209-5213. doi: 10.1021/acs.orglett.3c01655. Epub 2023 Jul 6.

Abstract

Elegant synthetic strategies for chromenopyrroles (azacoumestans) have been devised via cycloaddition of 2-hydroxychalcone/cyclic enones and alkyl isocyanoacetate, followed by lactonization. Herein, ethyl isocyanoacetate acts as a C-NH-C-C═O synthon contrary to its hitherto applications as a C-NH-C synthon. Subsequently, pentacyclic-fused pyrroles were also constructed from the o-iodo benzoyl chromenopyrroles using the Pd(II) catalyst.