Dearomatizing anionic cyclization of substituted N-cumyl-N-benzylbenzamides on treatment with LDA:: Synthesis of partially saturated substituted isoindolones

[GRAPHICS] On treatment with LDA, substituted N-benzylbenzamides (including those bearing electron withdrawing, electron-donating, or conjugating groups) become lithiated and cyclize to give, after aqueous quench, a range of partially saturated isoindolones as single regio- and stereoisomers, In general, the isoindolones resist rearomatization. Reaction of N-cumyl-N-benzylbenzamides leads to cyclized products which may be deprotected to give N-unsubstituted isoindolones.