title: Clarification of the stereochemical course of nucleophilic substitution of arylsulfonate-based nucleophile assisting leaving groups.
abstract: Secondary alcohols modified as tosylates, PEG-sulfonates, or quisylates undergo inversion of configuration at the reacting center when treated with lithium halide in acetone at reflux, where the PEG-sulfonates and quisylates are substantially more reactive. In sterically hindered cases, elimination is a competing process. In contrast, when treated with TiCl(4), simple secondary sulfonates give chloride products with partial inversion of configuration. Any observed retention of configuration in a given alkyl sulfonate substrate under these conditions is likely due to neighboring group participation or diastereoselective attack on a carbocation (or ion pair) rather than an S(N)i mechanism.
authors: Department of Chemistry, Imperial College London, London SW7 2AZ, UK. c.braddock@imperial.ac.uk
authors: D Christopher
authors: DC
authors: Braddock
authors: Rebecca H
authors: RH
authors: Pouwer
authors: Jonathan W
authors: JW
authors: Burton
authors: Phillip
authors: P
authors: Broadwith