Hydrogen Atom Transfer (HAT)-Mediated Remote Desaturation Enabled by Fe/Cr–H Cooperative Catalysis
作者:Yanjun Wan、Augustine K. Adda、Jin Qian、David A. Vaccaro、Peixian He、Gang Li、Jack R. Norton
DOI:10.1021/jacs.3c13085
日期:2024.2.21
An iron/chromium system (Fe(OAc)2, CpCr(CO)3H) catalyzes the preparation of β,γ- or γ,δ-unsaturated amides from 1,4,2-dioxazol-5-ones. An acyl nitrenoid iron complex seems likely to be responsible for C–H activation. A cascade of three H• transfer steps appears to be involved: (i) the abstraction of H• from a remote C–H bond by the nitrenoid N, (ii) the transfer of H• from Cr to N, and (iii) the abstraction
铁/铬体系(Fe(OAc) 2 、CpCr(CO) 3 H)催化从1,4,2-二恶唑-5-酮制备β,γ-或γ,δ-不饱和酰胺。酰基氮烯类铁络合物似乎可能负责 C-H 激活。似乎涉及三个 H• 转移步骤的级联:(i) 通过氮素 N 从远程 C-H 键中提取 H•,(ii) H• 从 Cr 转移到 N,以及 (iii)由Cr•从自由基取代基中抽象出H•。如果氮烯类化合物的形成是速率决定步骤,则观察到的动力学同位素效应与所提出的机制一致。 Fe/Cr 催化剂还可以将取代的 1,4,2-二恶唑-5-酮去饱和为 3,5-二烯酰胺。