We developed neutral iridium catalysts with chiral spiro phosphine-carboxy ligands (SpiroCAP) for asymmetrichydrogenation of unsaturated carboxylic acids. Different from the cationic Crabtree-type catalysts, the iridium catalysts with chiral spiro phosphine-carboxy ligands are neutral and do not require the use of a tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (BArF−) counterion, which is necessary
Highly enantioselective hydrogenation of α-oxy functionalized α,β-unsaturated acids catalyzed by a ChenPhos–Rh complex in CF<sub>3</sub>CH<sub>2</sub>OH
作者:Lin Yao、Jialin Wen、Shaodong Liu、Renchang Tan、Noel Marie Wood、Weiping Chen、Shengyong Zhang、Xumu Zhang
DOI:10.1039/c5cc09089j
日期:——
A Chenphos–Rh complex is demonstrated to be a highly efficient catalyst for asymmetric hydrogenation of α-oxy functionalized α,β-unsaturated carboxylic acidsviaan ionic interaction between the ligand and the substrate.
Highly active: Iridium complexes with chiral spiro aminophosphine ligands were synthesized and applied as catalysts for the asymmetrichydrogenation of α‐substituted acrylicacids (see scheme). The complexes were highly active catalysts, showing turnover frequencies of up to 6000 h−1, and catalyst loadings could be reduced to 0.01 mol %.