We present the first base‐free Fe‐catalyzed ester reduction applying molecular hydrogen. Without any additives, a variety of carboxylic acid esters and lactones were hydrogenated with high efficiency. Computations reveal an outer‐sphere mechanism involving simultaneous hydrogen transfer from the iron center and the ligand. This assumption is supported by NMR experiments.
Hydrogenation of esters to alcohols with a well‐defined iron iPr2PNP pincercomplex has been recently reported by us and other groups. We now introduce a novel and sterically less hindered Et2PNP congener that provides superior catalytic activity in the hydrogenation of various carboxylic acid esters and lactones compared to the known complex. Successful hydrogenation proceeds under relatively mild
Synergistic effect of additives on cyclopropanation of olefins
作者:Donghao Cheng、Deshun Huang、Yian Shi
DOI:10.1039/c3ob40751a
日期:——
An efficient cyclopropanation of olefins with Zn(CH2I)2, a catalytic amount of CCl3CO2H, and 1,2-dimethoxyethane at room temperature is described. A wide variety of olefins, including acid-sensitive substrates, can be cyclopropanated in 71–99% yield.