Functionalization of Rh III –Me Bonds: Use of “Capping Arene” Ligands to Facilitate Me–X Reductive Elimination
Functionalization of Rh III –Me Bonds: Use of “Capping Arene” Ligands to Facilitate Me–X Reductive Elimination
复制标题
Rh III – Me 键的功能化：使用“封端芳烃”配体促进 Me –X 还原消除
DOI：
10.1021/acs.organomet.1c00223
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发表时间：
2021
期刊：
影响因子：
2.8
通讯作者：
Gunnoe, T. Brent
中科院分区：
文献类型：
--
作者：
Gu, Shunyan;Chen, Junqi;Musgrave, Charles B.;Gehman, Zoë M.;Habgood, Laurel G.;Jia, Xiaofan;Dickie, Diane A.;Goddard, William A.;Gunnoe, T. Brent
我们展示了如何通过使用“封端芳烃”配体将甲烷活化催化剂的MeX产率从12%提高到90%。四种（FP）RhIII（Me）（TFA）2{FP =“封端芳烃”配体，包括8，8 ′-（1，2-亚苯基）二喹啉（6-FP）、8，8 ′-（1，2-萘）二喹啉（6-NPFP）、1，2-双（N-7-氮杂吲哚基）苯（5-FP）和1，2-双（N-7-氮杂吲哚基）萘（5-NPFP）}配合物。合成了这些配合物和（dpe）RhIII（Me）（TFA）2（dpe = 1，2-二-2-吡啶基乙烷），并测试了它们在MeX（X = TFA或卤化物）的还原消除中的性能。使用FP配体的目的是阻断配位位点以使RhIII复合物不稳定并促进MeX还原消除。基于单晶X射线衍射研究，6-FP和6-NPFP连接的Rh络合物具有比5-FP和5-NPFP Rh络合物短的Rh-芳烃距离;因此，预期5-FP络合物的Rh-芳烃相互作用比6-FP络合物弱。与我们的假设一致，5-FP和5-NPFP RhIII复合物在MeX的还原消除中表现出改进的性能（从12%到约60%产率）。通过使用化学氧化剂可以进一步改善MeX从（FP）RhIII（Me）（TFA）2中的还原消除。例如，添加2当量的AgOTf导致87（2）%的MeTFA产率，并且可以在90 °C下在CD 3CN中使用（5-FP）Rh（Me）（TFA）2实现。
We show how to improve the yield of MeX from CH4activation catalysts from 12% to 90% through the use of “capping arene” ligands. Four (FP)RhIII(Me)(TFA)2{FP = “capping arene” ligands, including 8,8′-(1,2-phenylene)diquinoline (6-FP), 8,8′-(1,2-naphthalene)diquinoline (6-NPFP), 1,2-bis(N-7-azaindolyl)benzene (5-FP), and 1,2-bis(N-7-azaindolyl)naphthalene (5-NPFP)} complexes. These complexes and (dpe)RhIII(Me)(TFA)2(dpe = 1,2-di-2-pyridylethane) were synthesized and tested for their performance in reductive elimination of MeX (X = TFA or halide). The FP ligands were used with the goal of blocking a coordination site to destabilize the RhIIIcomplexes and facilitate MeX reductive elimination. On the basis of single-crystal X-ray diffraction studies, the 6-FP and 6-NPFP ligated Rh complexes have Rh–arene distances shorter than those of the 5-FP and 5-NPFP Rh complexes; thus, it is expected that the Rh–arene interactions are weaker for the 5-FP complexes than for the 6-FP complexes. Consistent with our hypothesis, the 5-FP and 5-NPFP RhIIIcomplexes demonstrate improved performance (from 12% to ∼60% yield) in the reductive elimination of MeX. The reductive elimination of MeX from (FP)RhIII(Me)(TFA)2can be further improved by the use of chemical oxidants. For example, the addition of 2 equiv of AgOTf leads to 87(2)% yield of MeTFA and can be achieved in CD3CN at 90 °C using (5-FP)Rh(Me)(TFA)2.