Thiazolium salt-catalyzed [3 + 2 + 1] cyclization for the synthesis of trisubstituted 2-pyrones using arylglyoxals as a carbonyl source

Abstract

A new thiazolium salt-catalyzed [3 + 2 + 1] cyclization of acetylenedicarboxylates with arylglyoxals has been developed, enabling organocatalytic umpolung to access trisubstituted 2-pyrones with good yields via C–C bond cleavage, in which arylglyoxals played dual roles as a ring component as well as a carbonyl source. The reaction mechanism was proposed based on LC-MS analysis.