title: Catalytic asymmetric synthesis of secondary nitriles via stereoconvergent Negishi arylations and alkenylations of racemic α-bromonitriles.
abstract: The first method for the stereoconvergent cross-coupling of racemic α-halonitriles is described, specifically, nickel-catalyzed Negishi arylations and alkenylations that furnish an array of enantioenriched α-arylnitriles and allylic nitriles, respectively. Noteworthy features of this investigation include: the highly enantioselective synthesis of α-alkyl-α-aryl nitriles that bear secondary α-alkyl substituents; the first examples of the use of alkenylzinc reagents in stereoconvergent Negishi reactions of alkyl electrophiles; demonstration of the utility of a new family of ligands for asymmetric Negishi cross-couplings (a bidentate bis(oxazoline), rather than a tridentate pybox); in the case of arylzinc reagents, carbon-carbon bond formation at a remarkably low temperature (-78 °C), the lowest reported to date for an enantioselective cross-coupling of an alkyl electrophile; a mechanistic dichotomy between Negishi reactions of an unactivated versus an activated secondary alkyl bromide.
authors.affiliation: Department of Chemistry, Massachusetts Institute of Technology, Cambridge, 02139, United States.
authors.forename: Junwon
authors.initials: J
authors.lastname: Choi
authors.forename: Gregory C
authors.initials: GC
authors.lastname: Fu
mesh_terms: D002384:Catalysis; D015394:Molecular Structure; D009570:Nitriles / Q000138:chemical synthesis* / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D009570:Nitriles