α-Selective Ni-Catalyzed Hydroalumination of Aryl- and Alkyl-Substituted Terminal Alkynes: Practical Syntheses of Internal Vinyl Aluminums, Halides, or Boronates
Citations Over TimeTop 10% of 2010 papers
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 accessible. The derived alpha-vinyl halides and boronates can be synthesized through direct treatment with the appropriate electrophiles [e.g., Br(2) and methoxy(pinacolato)boron, respectively]. Ni-catalyzed hydroaluminations can be performed with as little as 0.1 mol % catalyst and on gram scale with equally high efficiency and selectivity.
Related Papers
- → Halogen exchange reactions between alkyl halides and aqueous hydrogen halides. A new method for preparation of alkyl halides.(1990)29 cited
- → Fast and Easy Halide Exchangein Aryl Halides(2003)11 cited
- → Reaction of alkyl halides with dialkyltins(1967)12 cited
- → The Use of S-Alkyl-N-Phenylthiuronium Picrates, Styphnates and Picrolonates for the Characterisation of Alkyl Halides(1960)2 cited
- → Conformational and Chiroptical Properties of Alkyl Halides(2009)