[2+2] Cycloaddition of electron-poor acetylenes to (E)-3-dimethylamino-1-heteroaryl-prop-2-en-1-ones: synthesis of highly functionalized 1-heteroaroyl-1,3-butadienes

Microwave-assisted [2+2] cycloaddition of (E)-3-dimethylamino-1-heteroaryl-prop-2-en-1-ones to dimethyl acetylenedicarboxylates gives (2E,3E)-dimethyl-2-[(dimethylamino)methylene]-3-(substituted)succinates in 8-91% yield. In the case of a 4,5-dihydrothiazoline derivative, cycloaddition also took place at the endocyclic C=N double bond. (C) 2010 Elsevier Ltd. All rights reserved.