Highly Chemoselective Multicomponent Biginelli‐Type Condensations of Cycloalkanones, Urea or Thiourea and Aldehydes

Abstract

Abstract The classical Biginelli reaction is considerably extended by use of cycloalkanones instead of 1,3‐dicarbonyl compounds. Use of TMSCl as a Lewis acid allowed one‐pot chemoselective multicomponent Biginelli reactions between cycloalkanones, urea or thiourea, and aldehydes. Under similar reaction conditions, thiourea exhibited different behavior to urea, and aliphatic aldehydes showed lower reactivity than aromatic aldehydes. A possible mechanism to account for the reaction is proposed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)