Investigations into the enantioselective C-protonation of prostereogenic enolate(s) derived from N, N′-diisopropyl-2-phenylpropanamide using suicide C-based proton sources

• Published in: Tetrahedron letters Vol. 45; no. 51; pp. 9469 - 9474
• Main Authors: Coumbarides, Gregory S., Eames, Jason, Ghilagaber, Stephanos, Suggate, Michael J.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 13-12-2004
• ISSN: 0040-4039; 1873-3581
• DOI: 10.1016/j.tetlet.2004.10.090

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The synthesis of enantiomerically enriched (−)-(
R)-
N,
N′-diisopropyl-2-phenylpropanamide was achieved in up to 69% enantiomeric excess by symmetrisation of the corresponding racemic amide by addition of
sec-BuLi (to give the corresponding achiral lithium enolate) and subsequent desymmetrisation by the addition of a chiral
C-based proton source. We discuss potential factors that may be responsible for this observed enantioselectivity and comment on the role of the chiral acid.