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Highly Enantiomerically Enriched Ketone Homoenolate Reagents Prepared by (−)‐Sparteine‐Mediated γ‐Deprotonation of Achiral 1‐Alkenyl Carbamates
Author(s) -
Seppi Michael,
Kalkofen Rainer,
Reupohl Jens,
Fröhlich Roland,
Hoppe Dieter
Publication year - 2004
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.200352966
Subject(s) - sparteine , deprotonation , chemistry , reagent , ketone , lithium (medication) , aryl , base (topology) , butyllithium , medicinal chemistry , stereochemistry , organic chemistry , ion , medicine , mathematical analysis , alkyl , mathematics , endocrinology
Homoenolate equivalents : Enantiotopos‐differentiating deprotonation of achiral 1‐alkenyl carbamates with the chiral base n ‐butyllithium/(−)‐sparteine yields configurationally stable lithium homoenolate equivalents. In a subsequent syn or anti substitution (see scheme), γ‐substituted O ‐(1‐aryl‐1‐alkenyl) N , N ‐diisopropylcarbamates are formed with high enantio‐ and diastereoselectivity.