- Mechanism of Dehydroacetoxylation of Methyl 3-Acetoxy-3-aryl-2-halogenopropanoates
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The rate of sodium methoxide-induced dehydroacetoxylation of the diesters p-RC6H4CH(OAc)CXHCO2Me (X= Br or Cl) has been studied as a function of the para-substituent.The results correspond to the para-substituent effects expected for proton abstraction from C-2, as estimated from the diastereoisomerisation of model compounds under similar conditions.This suggests that the elimination occurs via a carbanion mechanism, with C(2)-H bond-breaking rate-determining.The apparent insensitivity of the kinetic behaviour to configuration differences, together with the response of the reactions to the effect of the 3-substituent, is interpreted in terms of inductive stabilisation by the 2-halogen atom, which tends to localise the incipient negative charge at C-2, inhibiting distortion of its tetrahedral geometry.
- Cabaleiro, Mercedes C.,Garay, Raul O.
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p. 1091 - 1096
(2007/10/02)
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