Highly Enantioselective Iridium-Catalyzed Hydrogenation of Conjugated Trisubstituted Enones
作者:Bram B. C. Peters、Jira Jongcharoenkamol、Suppachai Krajangsri、Pher G. Andersson
DOI:10.1021/acs.orglett.0c04012
日期:2021.1.1
Asymmetric hydrogenation of conjugated enones is one of the most efficient and straightforward methods to prepare optically active ketones. In this study, chiral bidentate Ir–N,P complexes were utilized to access these scaffolds for ketones bearing the stereogenic center at both the α- and β-positions. Excellent enantiomeric excesses, of up to 99%, were obtained, accompanied with good to high isolated
Cellulose-supported chiral Rh nanoparticle (NP) catalysts have been developed.
纤维素支持的手性铑纳米颗粒(NP)催化剂已经被开发出来。
Chemoenzymatic Synthesis and Application of Bicyclo[2.2.2]octadiene Ligands: Increased Efficiency in Rhodium-Catalyzed Asymmetric Conjugate Additions by Electronic Tuning
作者:Yunfei Luo、Andrew J. Carnell
DOI:10.1002/anie.200907033
日期:2010.4.1
On your bi(cycle)ke! A series of 1,4‐dimethyl bicyclic [2.2.2] diene ligands with tunable substitution at the bridge positions was accessed using a lipase resolution and a high yielding six step sequence (see scheme). The bridgehead methyl groups improve efficiency allowing less aryl boronic acid to be used in the title reaction.
A series of novel chiral diene ligands (1R,4S)-L1, which are based on the bicyclo[2.2.1]heptadiene skeleton and are substituted with methyl and an ester group at the bridgehead carbons, were synthesized through rhodium-catalyzed asymmetric arylative bis-cyclization of 1,6-enyne 1 as a key step. The rhodium catalyst with one of the (1R,4S)-L1 ligands was used for the asymmetric bis-cyclization of 1
New asymmetricconjugatereduction of beta,beta-disubstituted alpha,beta-unsaturated ketones and esters was accomplished with alkoxylhydrosilanes in the presence of chiral rhodium(2,6-bisoxazolinylphenyl) complexes in high yields and high enantioselectivity. (E)-4-Phenyl-3-penten-2-one and (E)-4-phenyl-4-isopropyl-3-penten-2-one were readily reduced at 60 degrees C in 95 % ee and 98 % ee, respectively