Carbanions 730 VII. Structure and Reactivity of Lewis Acid Complexed Amino Carbanions 731 VIII. Amine Activation by BH 3 and Other Lewis Acids 732 IX. Diastereo-and Enantioselective Transformation 733 X. Future Prospects and Challenges 735 XI. Acknowledgments 735 XII. References and Footnotes 735 Scheme 27 Scheme 28

BF3 complexes of typical benzylic, allylic and saturated N-methyl tertiary amines were a-lithiated, with lithium tetramethylpiperidide (LTMP) or sec-butyllithium, and were treated with electrophiles.This Communication describes the concept of facilitating a-deprotonation of heteroatom compounds by complexation with a Lewis acid, and shows its utility for regioselective formation of C-C bonds in some tertiary amines (Scheme 1). $ Tertiary amines offer a real test of this idea since nitrogen, unlike phosphorus and sulphur, does not provide sufficient t Part of this work was presented at the 17th IUPAC International

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In dimethyl sulphoxide the dianions derived from 2,3or 3,4-dihydroxybenzaldehydes and 4-methylesculetin afford products corresponding to alkylation at the less acidic site while the monoanions give the isomeric phenols.

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