Synfacts 2005(1): 0111-0111  
DOI: 10.1055/s-2005-872212
Synthesis of Heterocycles
© Georg Thieme Verlag Stuttgart · New York

A Heterocyclic N-Oxide-Mediated Morita-Baylis-Hillman Reaction

Contributor(s): Victor Snieckus, Zhongdong Zhao
Y. S. Lin, C. W. Liu, T. Y. R. Tsai*
National Dong Hwa University, Hualien, Taiwan
Further Information

Publication History

Publication Date:
21 September 2005 (online)


This constitutes the first report of the use of a heterocyclic N-oxide, 1-methylimidazole 3-N-oxide (1) as an effective promoter for the Morita-Baylis-Hillman reaction. Aromatic aldehydes bearing EWG (NO2, CF3, Cl) or EDG (OMe, OH) undergo smooth condensation with α,β-unsaturated ketones and esters under solvent-less conditions in the presence of two equivalents of 1 to give products in low to excellent yields. As expected, aldehydes with EWGs (e.g. NO2) give better yields than those bearing EDGs (e.g. OMe). Substituted aryl, naphthalenyl, pyridyl, quinolinyl, furfuryl, and thiophenyl aldehydes were used. Replacement of the normally used strong Lewis base catalysts (such as DABCO) by 1 not only overcomes slow reaction rates but also reduces the formation of side products. Although two equivalents of 1 are required, it is regenerated.