Five ketones R1COCH2R2 (1a-e) were enolized in tetrahydrofuran solvent employing lithium arylamides with different electron-withdrawing and-donating substituents on the phenyl ring (4a-e). Enolate selectivity is unaffected by a moderate electron-releasing or- withdrawing group, but significantly enhanced by strong electron-withdrawing substituents to yield predominantly Z-enolate. Outstanding selectivity was achieved with lithium ...
