Reuter Matthew B, Cibuzar Michael P, Hammerton James, Waterman Rory
University of Vermont, Department of Chemistry, Discovery Hall, Burlington, VT 05401, USA.
Dalton Trans. 2020 Mar 3;49(9):2972-2978. doi: 10.1039/c9dt04870g.
Silicon-oxygen and silicon-nitrogen heterodehydrocoupling catalyzed by the commercially available cyclopentadienyl dicarbonyl iron dimer [CpFe(CO)2]2 (1) under photochemical conditions is reported. Reactions between alcohols and PhSiH3 with catalytic 1 under visible-light irradiation produced silyl ethers quantitively. Reactions between either secondary or tertiary silanes and alcohols also produced silyl ethers, however, these reactions were marked by their longer reaction times and lower conversions. Reactions of either primary or secondary amines and silanes with catalytic 1 demonstrated mixed efficiency, featuring conversions of 20-100%. Mechanistic study indicates that an iron silyl compound is unimportant in the bond-formation step and argues for either a nucleophilic alkoxide or amide intermediate. Most important, mechanistic study reveals that the most immediate hurdle in the catalysis is the poor activation of 1, demonstrating the necessity to fully activate the catalyst to realize the potential of iron in this reactivity.
据报道，在光化学条件下，市售的环戊二烯基二羰基铁二聚体[CpFe(CO)₂]₂（1）催化硅 - 氧和硅 - 氮杂脱氢偶联反应。在可见光照射下，醇与PhSiH₃在催化量的1存在下反应定量生成硅醚。仲硅烷或叔硅烷与醇之间的反应也生成了硅醚，然而，这些反应的特点是反应时间较长且转化率较低。伯胺或仲胺与硅烷在催化量的1存在下反应效率不一，转化率在20% - 100%之间。机理研究表明，铁硅化合物在键形成步骤中并不重要，并支持亲核醇盐或酰胺中间体的存在。最重要的是，机理研究表明催化过程中最直接的障碍是1的活化不足，这表明充分活化催化剂对于实现铁在这种反应性中的潜力至关重要。
