Tandem Frustrated Lewis Pair/Tris(pentafluorophenyl)borane-Catalyzed Deoxygenative Hydrosilylation of Carbon Dioxide
Tandem Frustrated Lewis Pair/Tris(pentafluorophenyl)borane-Catalyzed Deoxygenative Hydrosilylation of Carbon Dioxide
复制标题
DOI：
10.1021/ja105320c
复制
发表时间：
2010-08-11
影响因子：
15
通讯作者：
Parvez, Masood
中科院分区：
文献类型：
--
作者：
Berkefeld, Andreas;Piers, Warren E.;Parvez, Masood
由2,2,6,6-四甲基哌啶（TMP）和三（五氟苯基）硼烷[B(C(6)F(5))(3)]的2等量组成的受挫Lewis对体系活化二氧化碳形成硼酸氨基甲酸酯- tmph离子对。在三乙基硅烷的存在下，该物种被转化为氨基硅酯和已知的离子对[TMPH](+)[HB(C(6)F(5))(3)(-)，最近被证明通过氢化物从氢酸盐转移与CO(2)反应形成formatobate [TMPH](+)[HC(O)- ob (C(6)F(5))3]（-）。在额外的B(C(6)F(5))(3)（0.1-1.0当量）和过量的三乙基硅烷存在下，formatobate迅速氢硅化形成formatobate硅烷并再生[TMPH](+)[HB(C(6)F(5))3]（-）。再由B(C(6)F(5))(3)/Et(3)SiH体系将正丁硅烷迅速氢硅化成CH(4)，副产物为（Et(3)Si）(2)O。在低[Et(3)SiH]下，观察到中间CO(2)还原产物；添加更多的CO(2)/Et(3)SiH导致硅氢化反应恢复，表明这是一个强大的、有活性的串联催化系统，用于CO(2)脱氧还原为CH(4)。
The frustrated Lewis pair system consisting of 2 equiv of 2,2,6,6-tetramethylpiperidine (TMP) and tris(pentafluorophenyl)borane [B(C(6)F(5))(3)] activates carbon dioxide to form a boratocarbamate-TMPH ion pair. In the presence of triethylsilane, this species is converted to a silyl carbamate and the known ion pair [TMPH](+)[HB(C(6)F(5))(3)(-), which recently was shown to react with CO(2) via transfer of the hydride from the hydridoborate to form the formatoborate [TMPH](+)[HC(O)-OB(C(6)F(5))3](-). In the presence of extra B(C(6)F(5))(3) (0.1-1.0 equiv) and excess triethylsilane, the formatoborate is rapidly hydrosilated to form a formatosilane and regenerate [TMPH](+)[HB(C(6)F(5))3](-). The formatosilane in turn is rapidly hydrosilated by the B(C(6)F(5))(3)/Et(3)SiH system to CH(4), with (Et(3)Si)(2)O as the byproduct. At low [Et(3)SiH], intermediate CO(2) reduction products are observed; addition of more CO(2)/Et(3)SiH results in resumed hydrosilylation, indicating that this is a robust, living tandem catalytic system for the deoxygenative reduction of CO(2) to CH(4).