Sigmatropic Rearrangement on M-E Single and Double Bond System (M = Transition Metal, E = Main Group Element

在这个研究项目中，我们研究了(1)金属与主要基团元素如硅烯和锗配合物之间具有不饱和键的过渡金属配合物的合成和(2)不饱和键的反应性，特别是M-E键和M=E键(M=过渡金属，E=主族元素)之间的S型重排。硅基(硅烯)络合物被认为是过渡金属化合物介导的许多有机硅化合物转化的关键中间体。然而，由于硅烯配体的缺电子性质，这样的络合物太不稳定而无法分离。我们成功地用大量MES取代基(MES=2，4，6-C_6H_2Me_3)稳定了硅基(硅烯)配合物，并分离出了第一个硅基(硅烯)钨、钼和铁配合物。2-N，N-二甲氨基苯基-二甲基硅烷存在下，Cp^*W(CO)_3Me(Cp^*=η-C_5Me_5)与N-二甲氨基苯基二甲基硅烷反应生成了1，3-取代基从硅基迁移到硅烯配体，然后1，2-硅基从铁迁移到硅烯配体的二硅亚铁配合物。进一步的辐射导致1，2-芳基从硅基迁移到钨上形成碱性稳定的硅烯络合物，辐射得到了一种新型的具有Fe-Si-P三元环的金属环络合物。由于亚膦配位的硅烯配体的共振态的贡献，Fe-Si键具有不饱和性。因此，络合物与丙酮的反应是通过丙酮氧配位到硅烯配体上，然后插入到Si-P键中形成Fe-Si-O-C-P五元环。

In this research project, we have investigated (1) synthesis of transition-metal complexes with unsaturated bonding between metal and main group elements such as silylene and germylene complexes and (2) reactivities of the unsaturated bonding, especially sigmatropic rearrangement between the M-E and M=E bonds (M = transition metal, E = main group element).Silyl(silylene) complexes have been proposed as key intermediates in many transformations of organosilicon compounds mediated by transition metal compounds. However, such complexes are too unstable to isolate due to the electron-deficient nature of the silylene ligand. We have succeeded to stabilize the silyl(silylene) complexes kinetically using bulky Mes substituents (Mes = 2,4,6-C_6H_2Me_3) and isolated the first silyl(silylene)tungsten, molybdenum, and iron complexes. Reaction of the isolated silyl(silylene)iron complex with 'BuNC afforded a disilanyliron complex produced by 1,3-substituent migration from silyl to silylene ligand followed by 1,2-silyl migration from iron to silylene ligand.Photo-irradiation of Cp^*W(CO)_3Me (Cp^* = η-C_5Me_5) in the presence of (2-N,N-dimethylaminophenyl)dimethylsilane gave a silyl complex in which the amino group was coordinated to the tungsten atom. Further irradiation of the silyl complex caused 1,2-aryl migration from silyl to tungsten to form abase-stabilized silylene complex.Irradiation of phosphinosilyliron complex CpFe(CO)_2SiMe_2PPh_2 afforded a novel metallacycle complex with Fe-Si-P three-membered ring. The Fe-Si bond bears unsaturated character due to the contribution of a resonance form with a phosphino-coordinated silylene ligand. Thus reaction of the complex with acetone proceeded via coordination of acetone oxygen to the silylene ligand followed by insertion into the Si-P bond to form a Fe-Si-O-C-P five-membered ring.