Alpha-selective Ni-catalyzed hydroalumination of aryl- and alkyl-substituted terminal alkynes: practical syntheses of internal vinyl aluminums, halides, or boronates.

ABSTRACT: A method for Ni-catalyzed hydroalumination of terminal alkynes, leading to the formation of alpha-vinylaluminum isomers efficiently (>98% conv in 2-12 h) and with high selectivity (95% to >98% alpha), is described. Catalytic alpha-selective hydroalumination reactions proceed in the presence of a reagent (diisobutylaluminum hydride; dibal-H) and 3.0 mol % metal complex (Ni(dppp)Cl(2)) that are commercially available and inexpensive. Under the same conditions, but with Ni(PPh(3))(2)Cl(2), hydroalumination becomes highly beta-selective, and, unlike uncatalyzed transformations with dibal-H, generates little or no alkynylaluminum byproducts. All hydrometalation reactions are reliable, operationally simple, and practical and afford an assortment of vinylaluminums that are otherwise not easily ac

SUBMITTER: Gao F 

PROVIDER: S-EPMC2921967 | biostudies-literature | 2010 Aug

REPOSITORIES: biostudies-literature