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Generation of Enantiomerically Enriched Lithium Indenides by Means of (–)‐Sparteine: Structure, Stereoselective Substitution, and Solvent Effects
Author(s) -
Hoppe Inga,
Marsch Michael,
Harms Klaus,
Boche Gernot,
Hoppe Dieter
Publication year - 1995
Publication title -
angewandte chemie international edition in english
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 0570-0833
DOI - 10.1002/anie.199521581
Subject(s) - diastereomer , sparteine , stereoselectivity , racemization , chemistry , moiety , hexane , lithium (medication) , diethyl ether , solvent , crystallization , ligand (biochemistry) , ether , stereochemistry , medicinal chemistry , organic chemistry , medicine , biochemistry , receptor , endocrinology , catalysis
The thermodynamically controlled equilibration of the configurationally labile diastereomeric lithium 1‐alkylindenide/(–)‐sparteine complexes in diethyl ether/hexane combined with the crystallization of the diastereomer shown ( 1 ; R = Me, n Bu) results in a stereoselective addition of these complexes to carbonyl compounds with enantiofacial differentiation at the indenide moiety. In THF/hexane, however, the solvent displaces the chiral ligand and leads to complete racemization of the products.