title: Mechanistic interrogation of the asymmetric lithiation-trapping of N-thiopivaloyl azetidine and pyrrolidine.
abstract: A fundamental mechanistic study of the s-BuLi/chiral diamine-mediated lithiation-trapping of N-thiopivaloyl azetidine and pyrrolidine is reported. We show that lithiated thiopivalamides are configurationally unstable at -78 °C. Reaction then proceeds via a dynamic resolution of diastereomeric lithiated intermediates and this accounts for the variable sense and degree of asymmetric induction observed compared to N-Boc heterocycles.
authors.affiliation: Department of Chemistry, University of York, Heslington, York YO10 5DD, UK. peter.obrien@york.ac.uk.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Rayner
authors.forename: Joshua C
authors.initials: JC
authors.lastname: Smith
authors.forename: Charline
authors.initials: C
authors.lastname: Denneval
authors.forename: Peter
authors.initials: P
authors.lastname: O'Brien
authors.forename: Paul A
authors.initials: PA
authors.lastname: Clarke
authors.forename: Richard A J
authors.initials: RA
authors.lastname: Horan