title: Asymmetric hydrovinylation of unactivated linear 1,3-dienes.
abstract: Monosubstituted acyclic (E)-1,3-dienes undergo efficient hydrovinylation giving (Z)-3-alkylhexa-1,4-dienes upon treatment with catalytic amounts of bidentate phosphine-CoCl(2) complexes {[P~P](CoCl(2))} and Me(3)Al in an atmosphere of ethylene. The regioselectivity of the reaction (i.e., 1,4- or 1,2-addition) depends on the nature of the ligand and temperature at which the reaction is carried out. Complexes derived from (RR)-DIOP and (SS)-BDDP at -45 degrees C give very high enantioselectivities for several prototypical 1,3-dienes. In sharp contrast to the corresponding Ni(II)-catalyzed hydrovinylation, 1-aryl-substituted 1,3-dienes give almost exclusively achiral linear 1,4-addition products, unless the 2-position is also substituted. Solid-state structures of the precatalysts are presented.
authors.affiliation: Department of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, USA.
authors.forename: Rakesh K
authors.initials: RK
authors.lastname: Sharma
authors.forename: T V
authors.initials: TV
authors.lastname: RajanBabu
mesh_terms: D000466:Alkadienes / Q000138:chemical synthesis* / Q000737:chemistry; D002384:Catalysis; D003035:Cobalt / Q000737:chemistry; D010720:Phosphines / Q000737:chemistry; D014753:Vinyl Compounds / Q000138:chemical synthesis*
chemical_list: D000466:Alkadienes; D010720:Phosphines; D014753:Vinyl Compounds; D003035:Cobalt; C018021:cobaltous chloride