On the mechanism of the reaction of enamines and dimethyl acetylenedicarboxylate (DMAD) in polar and apolar solvents

GW Visser, W Verboom, WP Trompenaars…

Index: Visser, G. W.; Verboom, W.; Trompenaars, W. P.; Reinhoudt, D. N. Tetrahedron Letters, 1982 , vol. 23, # 11 p. 1217 - 1220

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Citation Number: 8

Abstract

We have measured the rates of the reaction of dimethyl 4-(1-pyrrolidinyl)-2,3-thiophenedicarboxylate with DMAD at 100° both in 1-butanol and in toluene and we found that the reaction in the polar solvent is only about twenty times faster than that in the apolar solvent. Eberbach and Carré 4 also reported no difference in the rate of reaction of a dihydroazepine with DMAD in solvents of different polarity although in acetonitrile the rearranged [2+2]-cycloadduct is formed ...