Manganese‐Catalyzed Asymmetric Hydrogenation of Quinolines Enabled by π–π Interaction**
作者:Chenguang Liu、Mingyang Wang、Shihan Liu、Yujie Wang、Yong Peng、Yu Lan、Qiang Liu
DOI:10.1002/anie.202013540
日期:2021.3
The non‐noble metal‐catalyzed asymmetric hydrogenation of N‐heteroaromatics, quinolines, is reported. A new chiral pincer manganese catalyst showed outstanding catalytic activity in the asymmetric hydrogenation of quinolines, affording high yields and enantioselectivities (up to 97 % ee). A turnover number of 3840 was reached at a low catalyst loading (S/C=4000), which is competitive with the activity
报道了非贵金属催化的N-杂芳族化合物喹啉的不对称氢化。一种新型手性钳式锰催化剂在喹啉的不对称氢化中表现出出色的催化活性,提供了高收率和对映选择性(高达97%ee)。在低催化剂负载量(S / C = 4000)下,达到了3840的周转率,与该反应中最有效的贵金属催化剂的活性相竞争。对映选择性的精确调节通过π-π相互作用来保证。
Enantioselective Synthesis of Tetrahydroquinolines by Borrowing Hydrogen Methodology: Cooperative Catalysis by an Achiral Iridacycle and a Chiral Phosphoric Acid
作者:Ching Si Lim、Thanh Truong Quach、Yu Zhao
DOI:10.1002/anie.201703704
日期:2017.6.12
We report herein the highly enantioselective synthesis of 2‐substituted tetrahydroquinolines through borrowing hydrogen, a process recognized for its environmentally benign and atom‐economical nature. The use of an achiral iridacycle complex in combination with a chiralphosphoricacid as catalysts was the key to the development of this highly efficient and enantioselective transformation.
AbstractThis work deals with the development of a new family of planar chiral phosphoric acids based on a ferrocenophane/paracyclophane scaffold. The synthetic approach has been improved by taking advantage of a chiral phosphorylating agent to access enantiomerically enriched acids via diastereomers separation. These phosphoric acids have been used as catalysts for the enantioselective H‐transfer reduction of α‐substituted quinolines with Hantzsch esters. Optimization of both the catalyst and the Hantzsch reductant allowed ee values in the range 82–92% to be attained starting from α‐arylquinolines.magnified image