title: Mechanistic variations in ionic hydrogenation of unsaturated phosphine and amine boranes.
abstract: Internal hydride transfer occurs when tethered carbocations are generated from unsaturated phosphine or phosphinite boranes. 3-Methylenecyclohexyl-derived boranes 12 or 18 react with MsOH to give ionic hydrogenation products with high syn-selectivity. With unsaturated amine boranes, initial hydrogen evolution gives BH(2)(OMs) complexes, but IH occurs using excess MsOH in a slower second stage. A diastereoselective reaction occurs from 26b using camphorsulfonic acid (first stage) and MsOH (second stage), affording 33 (68% ee) after hydrolysis.
authors.affiliation: Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA.
authors.forename: Timothy S
authors.initials: TS
authors.lastname: De Vries
authors.forename: Supriyo
authors.initials: S
authors.lastname: Majumder
authors.forename: Angela M
authors.initials: AM
authors.lastname: Sandelin
authors.forename: Guoqiang
authors.initials: G
authors.lastname: Wang
authors.forename: Edwin
authors.initials: E
authors.lastname: Vedejs
mesh_terms: D000588:Amines / Q000737:chemistry*; D001880:Boranes / Q000737:chemistry*; D006865:Hydrogenation; D007477:Ions / Q000737:chemistry; D015394:Molecular Structure; D010720:Phosphines / Q000737:chemistry*
chemical_list: D000588:Amines; D001880:Boranes; D007477:Ions; D010720:Phosphines; C044646:phosphine