The nickel equivalent of Karstedt catalyst [Ni(eta-CH2=CHSiMe2)(2)O}(2)mu-(eta-CH2=CHSiMe2}(2)O}] (1) appeared to be a very efficient catalyst for dehydrogenative coupling of vinyl derivatives (styrene, vinylsilanes, vinylsiloxanes) with trisubstituted silanes HSi(OEt)(3), HSiMe2Ph. The reaction occurs via three pathways of dehydrogenative coupling, involving formation of an unsaturated compound as the main product as well as a hydrogenated olefin (DS-1) pathway, hydrogenated dimeric olefin (DS-2) and dihydrogen (DC), respectively. The reaction is accompanied by side hydrosilylation. Stoichiometric reactions of 1 with styrene and triethoxysilane, in particular synthesis of the bis(triethoxysilyl) (divinyltetramethyldisiloxane) nickel complex 3 and the first documented insertion of olefin (styrene) into Ni-Si bond of complex 3, as well as all catalytic data have allowed us to propose a scheme of catalysis of this complex reaction by 1. (C) 2000 Elsevier Science S.A. All rights reserved.
Preparation of Organopolysiloxanes from Sodium Trimethylsilanolate
作者:Leo H. Sommer、Larry Q. Green、Frank C. Whitmore
DOI:10.1021/ja01177a524
日期:1949.9
Treatment of alkyltriethoxysilanes with amberlyst 15 cation-exchange resin in the presence of hexamethyldisiloxane