Isothiourea-Mediated One-Pot Synthesis of Trifluoromethyl Substituted 2-Pyrones

A one-pot isothiourea-mediated Michael addition/lactonization/thiol elimination cascade sequence for the formation of 4,6-disubstituted and 3,4,6-trisubstituted 2-pyrones from (phenylthio)acetic acids and alpha,beta-unsaturated trifluoro-Methyl ketones is described. The synthesis of a COX-2 inhibitor and the wide-ranging derivatization of the 2-pyrone moiety to trifluoromethyl substituted aromatics and heteroaromatics is also disclosed.