posted on 2024-03-13, 12:35authored byPing Guo, Yan Chen, Lei Tao, Shufang Ji, Ruixue Zhang, Zedong Zhang, Xiao Liang, Dingsheng Wang, Yadong Li, Jie Zhao
A heterogeneous
iridium single-atom site catalyst (Ir-SA) was synthesized
and investigated in catalyzing the carbene insertion reaction with
challenging α-alkyl diazo ester substrates. With only 0.23 mol
% catalyst loading, our Ir-SA demonstrated remarkable performance
in heterogeneous carbene N–H bond insertion reactions involving
various (hetero) aryl amines coupled with α-alkyl diazo esters.
Notably, in the case of using a chiral diamino substrate with two
reactive sites, Ir-SA exhibited high selectivity toward single carbene
N–H insertion, leading to the generation of a class of unsymmetric
chiral diamino ligands. Further mechanism study revealed that the
lower activation barrier associated with the single N–H bond
insertion step, as compared to either β-hydride elimination
or downstream dual N–H bond insertion, accounted for the remarkable
selectivity observed in this carbene insertion reaction catalyzed
by Ir-SA.