Zirconium-mediated reactions of alkylpyrazines and alkynes. Synthesis of highly substituted alkylpyrazines
作者:Anil S. Guram、Richard F. Jordan
DOI:10.1021/jo00048a038
日期:1992.10
Sequential one-pot addition of alkylpyrazines, alkynes, and a proton source to a solution of Cp2Zr(Me)(THF)+ (1) in CH2Cl2 at room temperature affords (E)-alkenyl-substituted alkylpyrazines 2-10 in excellent yields. The regio- and stereoselectively observed in these reactions is similar to those observed previously for related early transition metal-mediated reactions and is ascribed to steric and Si electronic effects. Conventional synthetic organic manipulation of the alkenylpyrazines provides easy access to a variety of highly substituted alkylpyrazines including tri- and tetrasubstituted alkylpyrazines 13, 17-20, dibromoalkylpyrazine 14, bromoalkylpyrazine 15, and epoxyalkylpyrazine 16.