Unusual Regioselectivity of the Dipolar Cycloaddition Reactions of Nitrile Oxides and Tertiary Cinnamides and Crotonamides1

MA Weidner-Wells, SA Fraga-Spano…

Index: Weidner-Wells, Michele A.; Fraga-Spano, Stephanie A.; Turchi, Ignatius J. Journal of Organic Chemistry, 1998 , vol. 63, # 18 p. 6319 - 6328

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Citation Number: 53

Abstract

Benzonitrile oxides undergo 1, 3-dipolar cycloaddition reactions with methyl cinnamate to produce the 5-phenyl and 4-phenyl regioisomers in approximately an 80: 20 ratio. However, use of N, N-diethylcinnamide as the dipolarophile unexpectedly resulted in the formation of the 5-phenyl and 4-phenyl regioisomers in a 23: 77 ratio. Studies have shown that this phenomena occurs only for tertiary cinnamides. In addition, it has been demonstrated that ...