Isosterically designed chiral catalysts: Rationale, optimization and their application in enantioselective nucleophilic addition to aldehydes
作者:En Gao、Qiao Li、Lili Duan、Lin Li、Yue-Ming Li
DOI:10.1016/j.tet.2020.131648
日期:2020.11
enantioselective nucleophilic addition to aldehydes. In the presence of 10 mol% of chiral ligand 1b, enantioselective addition of diethylzinc to aldehydes provided the corresponding secondary alcohols in up to 90% isolated yield and up to 99% ee. Similarly, using 3e as chiral ligand, enantioselective arylation and alkynylation of aldehydes also proceeded readily, leading to the desired chiral alcohols in up to
Axially Chiral NHC−Pd(II) Complexes in the Oxidative Kinetic Resolution of Secondary Alcohols Using Molecular Oxygen as a Terminal Oxidant
作者:Tao Chen、Jia-Jun Jiang、Qin Xu、Min Shi
DOI:10.1021/ol063061w
日期:2007.3.1
see text] Axially chiral N-heterocyclic carbene (NHC) Pd(II) complexes were prepared from optically active 1,1'-binaphthalenyl-2,2'-diamine (BINAM) and H8-BINAM and applied in the oxidativekineticresolution of secondaryalcoholsusing molecular oxygen as a terminal oxidant. The corresponding sec-alcohols can be obtained in good yields with moderate to good enantioselectivities.
Manganese complex-catalyzed oxidation and oxidative kinetic resolution of secondary alcohols by hydrogen peroxide
作者:Chengxia Miao、Xiao-Xi Li、Yong-Min Lee、Chungu Xia、Yong Wang、Wonwoo Nam、Wei Sun
DOI:10.1039/c7sc00891k
日期:——
manganese catalyst with a low loading and hydrogen peroxide as an environmentally benign oxidant in the presence of a small amount of sulfuric acid as an additive; the product yields were high (up to 93%) in the alcohol oxidation and the enantioselectivity was excellent (>90% ee) in the OKR of secondary alcohols. Mechanistic studies revealed that the alcohol oxidation occurs via a hydrogen atom (H-atom)
采用低负载量的合成锰催化剂和过氧化氢作为环境友好的氧化剂,并添加少量硫酸作为添加剂,实现了仲醇的高效催化氧化和氧化动力学拆分(OKR);醇氧化反应产物收率高(可达93%),仲醇OKR对映选择性优良(>90% ee )。机理研究表明,醇氧化是通过从醇底物的 α-CH 键上夺取一个氢原子(H 原子)以及亲电子 Mn-oxo 物质的双电子过程而发生的。密度泛函理论计算揭示了手性高价锰氧配合物从R-和S-对映体的α-CH键夺取H原子的反应能垒的差异,支持了仲醇OKR的实验结果。
Chemo- and Enantioselective Addition and β-Hydrogen Transfer Reduction of Carbonyl Compounds with Diethylzinc Reagent in One Pot Catalyzed by a Single Chiral Organometallic Catalyst
作者:Huayin Huang、Hua Zong、Guangling Bian、Ling Song
DOI:10.1021/acs.joc.5b01871
日期:2015.12.18
as the catalyst, the asymmetric β-H transfer reduction of aromatic α-trifluoromethyl ketones and enantioselective addition of aromatic aldehydes with Et2Zn in one pot were successfully realized, affording the corresponding additive products of secondary alcohols in high yields (up to 99%) with excellent enantioselectivities (up to 98% ee) and the reduction products of α-trifluoromethyl alcohols in good
Chiral C2-symmetric 2,5-disubstituted pyrrolidine derivatives as catalytic chiral ligands in the reactions of diethylzinc with aryl aldehydes
作者:Min Shi、Yukihiro Satoh、Yukio Masaki
DOI:10.1039/a803336f
日期:——
Two kinds of chiral C2-symmetric 2,5-disubstituted pyrrolidine derivatives having a β-aminoalcohol moiety have been successfully synthesized and their catalytic abilities of chiral induction have been examined in the reactions of diethylzinc with arylaldehydes. The production of sec-alcohols having R-absolute configuration could be achieved in very high chemical yield (85–95%) and very high enantiomeric