title: Highly diastereoselective lithiation and substitution of an (S)-prolinyl thiocarbamate via sterically homogeneous lithio(thiocarbamate): synthesis of enantiomerically pure prolinethiols.
abstract: Highly diastereoselective lithiation-substitution reactions of an (S)-proline derived S-alkyl thiocarbamate was accomplished. The configuration of the predominant alkyllithium species and the stereochemical course of the electrophilic substitution reactions are deduced by a combination of X-ray crystal structure analysis, NMR spectroscopic studies, deuteration/dedeuteration experiments, and quantum chemical calculations. The lithium intermediate (S,S)-9 was found to be kinetically and thermodynamically favoured, whereas (S,R)-9 rapidly epimerizes.
authors.affiliation: Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstrasse 40, 48149 Münster, Germany.
authors.forename: Ravindra P
authors.initials: RP
authors.lastname: Sonawane
authors.forename: Christian
authors.initials: C
authors.lastname: Mück-Lichtenfeld
authors.forename: Roland
authors.initials: R
authors.lastname: Fröhlich
authors.forename: Klaus
authors.initials: K
authors.lastname: Bergander
authors.forename: Dieter
authors.initials: D
authors.lastname: Hoppe