A simple and efficient sequential (3+2) annulation toward the construction of a novel contiguous dispiroheterocyclic scaffold

Abstract

A diastereoselective (3+2) annulation of 4-isothiocyanato pyrazolones and 2-arylidene-indan-1,3-dione in the presence of 4-dimethylaminopyridine is explored. A wide range of novel dispiroheterocyclic products were achieved in high yield (up to 95 %) and excellent diastereoselectivity (up to >20:1 dr) via a simple sequential Michael addition/cyclization.