Platinum oxide catalyzed hydrosilylation of unsymmetrical internal aryl alkynes under ortho-substituent regiocontrol.
[chemical reaction: see text]. PtO2- and H2PtCl6-catalyzed hydrosilylation of internal aryl alkynes having a para or an ortho substituent with triethylsilane are discussed and compared. The regioselectivity of the H-Si bond addition was found to be controlled by the ortho substituent rather than the nature of the platinum catalyst. Arylalkynes with an ortho substituent, regardless of its electronic nature, directed the silyl substituent mainly to the alpha-position. PtO2 proved to be a versatile and powerful catalyst compared to H2PtCl6 since it prevents the alkyne reduction.
Hamze
Abdallah
A
Laboratoire de Chimie Thérapeutique, BioCIS - CNRS (UMR 8076), Université Paris-Sud XI, Faculté de Pharmacie, rue J.B. Clément, 92296 Châtenay-Malabry Cedex, France.
Provot
Olivier
O
Alami
Mouâd
M
Brion
Jean-Daniel
JD