Kinetics of eliminations of some ethyl 2-cyano-5-oxopentanoates

ABSTRACT

The rates of elimination were determined for the reaction of ethyl 2-cyano-5-oxo-5-phenyl-3-[p-substituted phenyl] pentanoates Ia-f, and ethyl 2-cyano-5-oxo-3-phenyl-5-[p-substituted phenyl] pentanoates Ig- k, with sodium ethoxide in absolute ethanol. The products were found to be the corresponding substituted propenones IIa-k. Linear free energy correlation was found to give a positive reaction constant [rho]. A mechanistic E1cB mode was suggested and the reaction transition state is of the carbanion character