Journal Article Cyclic Model for the Asymmetric Conjugate Addition of Organolithiums with Enoates

Nishimura, Katsumi  ,  Fukuyama, Naoshi  ,  Yamashita, Mitsuaki  ,  Sumiyoshi, Takaaki  ,  Yamamoto, Yasutomo  ,  Yamada, Ken-ichi  ,  Tomioka, Kiyoshi

47 ( 15 )  , pp.2256 - 2264 , 2015-07-21 , Thieme Publishing Group
The chiral diether ligand controlled asymmetric conjugate addition of organolithiums to nona-2, 7-dienedioates preferentially proceeds via the s-cis conformation with coordination of the carbonyl oxygen atom to the lithium to give a lithium E-enolate intermediate. Subsequent intramolecular conjugate addition of the enolate also proceeds via a cyclic transition state involving the lithium and the s-cis-enoate, resulting in trans, trans-trisubstituted cyclohexanes with high enantiomeric excesses and yields.

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