title: Mechanistic insights on the stereoselective nucleophilic 1,2-addition to sulfinyl imines.
abstract: The asymmetric nucleophilic 1,2-addition of (S)-N-benzylidene-2-methylpropane-2-sulfinamide with methylmagnesium bromide and methyllithium has been investigated using DFT(B3LYP) computations. The calculated ratio of the two diastereomers agrees with experimental observations, and the factors that determine the diastereomeric ratio are discussed. The preference for the E isomer and the rapid equilibrium between the E and Z isomers of N-tert-butanesulfinyl imine are two key features for understanding the mechanism of this reaction. Methylmagnesium bromide and methyllithium have bifunctional roles, acting as both Lewis acid and nucleophile, and the Lewis acid character plays a determining role in the stereoselectivity of the reaction.
authors.affiliation: Department of Chemistry, University of Oslo , P.O. Box 1033, Blindern, N-0315 Oslo, Norway.
authors.forename: Martin
authors.initials: M
authors.lastname: Hennum
authors.forename: Heike
authors.initials: H
authors.lastname: Fliegl
authors.forename: Lise-Lotte
authors.initials: LL
authors.lastname: Gundersen
authors.forename: Odile
authors.initials: O
authors.lastname: Eisenstein
mesh_terms: D001597:Benzylidene Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D001965:Bromides / Q000737:chemistry; D007097:Imines / Q000737:chemistry*; D058116:Lewis Acids / Q000737:chemistry*; D017616:Magnesium Compounds / Q000737:chemistry; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry; D013237:Stereoisomerism; D013452:Sulfonium Compounds / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: C000592416:(S)-N-benzylidene-2-methylpropane-2-sulfinamide; D001597:Benzylidene Compounds; D001965:Bromides; D007097:Imines; D058116:Lewis Acids; D017616:Magnesium Compounds; C481933:N-tert-butanesulfinylimino ester; D009942:Organometallic Compounds; D013452:Sulfonium Compounds; C520093:methyllithium; C586611:magnesium bromide