Synthesis of substituted benzoates using a rhodium-mediated Hopf cyclization of 1,3-dien-5-ynes accessed from 2-pyrones

Abstract

The synthesis of substituted benzoates from 1,3-dien-5-ynes that are readily accessed from 2-pyrones is described. Highlighted is a 2-pyrone remodeling strategy in which a 3-alkynyl-2-pyrone is selectively opened in a 1,6-fashion using sodium cyanide to provide dienynes that upon treatment with sub-stoichiometric amounts of [Rh(CO)2Cl]2 at elevated temperature furnish the desired benzoate.