Regioselectivity homoenolate anion equivalents

Factors influencing the regioselectivity of alkylation of allylic anions continue to be studied, a-Alkylation of the keten thioacetalide anion (13) is favoured by hard leaving groups/ whereas the a-aminonitrile anion (14) reacts with ketones in the a-position at low temperature (-78 °C), but behaves as a homoenolate equivalent (y-attack) at At the higher temperature, competing aldol... 

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