One-pot assembly of pyrrolyl-pyrrolo[1,2-c]thiazoles via cascade addition-cyclization of 2-acylethynylpyrroles with sodium sulfide

A transition metal- and catalyst-free cascade assembly of pyrrolyl-pyrrolo[1,2-c]thiazoles from 2-acylethynylpyrroles and sodium sulfide has been developed. The assembly rapidly proceeds under mild conditions (dioxane/H2O, room temperature, 1 h) to furnish target products in up to 88% yield and strictly Z-configuration of alkenone moiety. Regio- and stereoselectivity of the reaction, availability and structural diversity of the substrates, air tolerance, and chromatography free purification are advantages of the synthesis. The synthesized pyrrolyl-pyrrolo[1,2-c]thiazoles contain multiple reactive sites available for further modifications, and, therefore, represent interest for medicinal chemistry and materials science.