Itazaki Masumi, Nishihara Yasushi, Osakada Kohtaro
Chemical Resources Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan.
J Org Chem. 2002 Oct 4;67(20):6889-95. doi: 10.1021/jo020293+.
PtI(2)(PPh(3))(2) catalyzes hydrosilylation of 2,2-diphenyl-1-methylenecyclopropane with HSiEt(3), HSiPh(3), HSiEt(2)Ph, HSiPhCl(2), and HSiCl(3) under solvent-free conditions at 140 degrees C to produce the silyl compounds with a (2,2-diphenylcyclopropyl)methyl substituent in moderate to high yields without ring-opening of the substrate. PtI(2)(PPh(3))(2) is converted by the reaction into PtH(I)(PPh(3))(2), which also catalyzes the hydrosilylation of the methylenecyclopropanes. The reaction of 2-phenyl-1-methylenecyclopropane, 2-methyl-2-phenyl-1-methylenecyclopropane, 2,2-diphenethyl-1-methylenecyclopropane, and alkylidenecyclopropanes with HSiEt(3) catalyzed by PtI(2)(PPh(3))(2) causes addition of hydrosilane to the substrate accompanied by ring-opening. 2,2-Diphenyl-1-methylenecyclopropane undergoes ring-opening isomerization in the presence of HSi(OEt)Me(2) and Pt(PEt(3))(3) catalyst to give 1,1-diphenyl-1,3-butadiene. The pathways for the hydrosilylation and the isomerization are discussed.
PtI₂(PPh₃)₂在无溶剂条件下于140℃催化2,2 - 二苯基 - 1 - 亚甲基环丙烷与HSiEt₃、HSiPh₃、HSiEt₂Ph、HSiPhCl₂和HSiCl₃的硅氢化反应，以中等到高的产率生成具有(2,2 - 二苯基环丙基)甲基取代基的硅基化合物，且底物不开环。反应过程中PtI₂(PPh₃)₂转化为PtH(I)(PPh₃)₂，后者也能催化亚甲基环丙烷的硅氢化反应。PtI₂(PPh₃)₂催化2 - 苯基 - 1 - 亚甲基环丙烷、2 - 甲基 - 2 - 苯基 - 1 - 亚甲基环丙烷、2,2 - 二苯乙基 - 1 - 亚甲基环丙烷和亚烷基环丙烷与HSiEt₃的反应会使硅烷加成到底物上并伴随开环。2,2 - 二苯基 - 1 - 亚甲基环丙烷在HSi(OEt)Me₂和Pt(PEt₃)₃催化剂存在下发生开环异构化生成1,1 - 二苯基 - 1,3 - 丁二烯。文中讨论了硅氢化反应和异构化反应的途径。
