SYNTHETIC APPLICATIONS OF THE BETA-LITHIATION OF BETA-ARYL SECONDARY AMIDES - DIASTEREOSELECTIVE AND ENANTIOSELECTIVE SUBSTITUTIONS

The sequence of beta-lithiation and electrophilic substitution of beta -aryl secondary amides is reported. The lithiations occur regioselecti vely at the beta-position, and the resulting lithiated intermediates c an be reacted with a wide range of electrophiles to give substituted p roducts. Reactions of beta-lithiated amides bearing an alpha-substitue nt provide substituted products with high diastereoselectivity, Electr ophilic substitutions of beta-lithiated N-methylamides in the presence of the chiral diamine (-)-sparteine provide highly enantioenriched pr oducts. The methodology is used to synthesize enantioenriched beta-ary l beta-substituted amides, acids, and lactones.