Influence of substituents on regioselectivity of vinyllithium formation with acrylic acid Derivatives

β-Alkoxy, β-dialkylamino, and β-N-alkylacylamino substituents determine the regioselectivity of the vinylic deprotonation of acrylic ester and nitrile derivatives: either α- or β-vinyllithium species may be generated. The corresponding acrylamides or systems with additional α-alkyl or α-methylmercapto substituents are lithiated at β-position.