Rhodium(I) Complexes with Ligands Based on N-Heterocyclic Carbene and Hemilabile Pyridine Donors as Highly <i>E</i> Stereoselective Alkyne Hydrosilylation Catalysts
作者:Judith P. Morales-Cerón、Patricia Lara、Joaquín López-Serrano、Laura L. Santos、Verónica Salazar、Eleuterio Álvarez、Andrés Suárez
DOI:10.1021/acs.organomet.7b00361
日期:2017.7.10
substitution at the 6-position of the pyridine donor serve as efficient E-selective alkyne hydrosilylation catalyst precursors. Particularly, when the steric hindrance of the picolyl fragment is increased, a catalyst precursor exhibiting high catalytic activities (TOF up to 500 h–1 at S/C ratios of 1000) and excellent E selectivities (E/α ratio ≥95/5) in the hydrosilylation of a series of aryl, alkyl, and
包含吡啶供体6-位取代度不同的吡啶甲基-NHC(NHC = N-杂环卡宾)配体的阳离子铑(I)络合物可作为有效的E选择性炔烃氢化硅烷化催化剂前体。特别是,当甲基吡啶基片段的空间位阻增加时,催化剂前体表现出高催化活性(S / C比为1000时,TOF高达500 h –1)和极好的E选择性(E在一系列芳基,烷基和官能化的末端炔烃与碳-和烷氧基硅烷的氢化硅烷化反应中,获得了/α比≥95/ 5)。Rh配合物中的吡啶甲基-NHC配体由于吡啶片段的半不稳定配位作用而在溶液中表现出动态行为。初步的机理研究支持了由Rh配合物和硅烷低浓度生成的Rh甲硅烷基氢化物参与炔烃的氢化硅烷化反应,并与Chalk–Harrod型机理的假设相一致。