Selective CH Bond Functionalization of 2-(2-Thienyl)pyridine by a Rhodium N-Heterocyclic Carbene Catalyst
作者:Laura Rubio-Pérez、Manuel Iglesias、Ricardo Castarlenas、Victor Polo、Jesús J. Pérez-Torrente、Luis A. Oro
DOI:10.1002/cctc.201402507
日期:2014.11
support that the reaction proceeds by initial κ1N coordination of 2‐(2‐thienyl)pyridine followed by the loss of H2 to afford the active catalyst. Subsequently, cyclometalation of 2‐(2‐thienyl)pyridine, coordination of the unsaturated substrate (alkyne or alkene) at the vacant position trans to the hydride, and reductive elimination of the thiophene moiety occur. Finally, cyclometalation of the thiophene
[Rh(μ-Cl)(H)2(IPr)] 2(IPr = 1,3-双-(2,6-二异丙基苯基)咪唑-2-亚烷基)催化2-(2-噻吩基)的选择性官能化吡啶与一系列烯烃和内部炔烃有效结合。在关键反应中间体的鉴定和通过NMR光谱研究其反应性的基础上,提出了催化循环。在DFT水平支撑,通过初始κ反应进行理论计算1 ñ 2-(2-噻吩基)吡啶的协调,接着H的损失2,得到活性催化剂。随后,在空闲位置2-(2-噻吩基)吡啶,所述不饱和底物(炔或烯烃)的协调的环金属化反生成氢化物,并还原除去噻吩部分。最后,噻吩部分的环金属化使氢化物顺式变为不饱和底物,这导致迁移插入RhH键并随后还原除去官能化产物。