Axially 4,4′-di-tert-butyl TunePhos-type chiral diphosphine ligand: synthesis and applications in asymmetric hydrogenation
摘要:
Axially 4,4'-di-tert-butyl TunePhos-type chiral diphosphine ligand was designed and synthesized by means of central-to-axial chirality transfer. Up to 99% and 98% ee have been achieved in Ru-catalyzed hydrogenation of beta-alkyl and beta-aryl-substituted beta-keto esters, respectively. (C) 2008 Elsevier Ltd. All rights reserved.
A New Class of Versatile Chiral-Bridged Atropisomeric Diphosphine Ligands: Remarkably Efficient Ligand Syntheses and Their Applications in Highly Enantioselective Hydrogenation Reactions
作者:Liqin Qiu、Fuk Yee Kwong、Jing Wu、Wai Har Lam、Shusun Chan、Wing-Yiu Yu、Yue-Ming Li、Rongwei Guo、Zhongyuan Zhou、Albert S. C. Chan
DOI:10.1021/ja0602694
日期:2006.5.1
A series of chiral diphosphineligands denoted as PQ-Phos was prepared by atropdiastereoselective Ullmann coupling and ring-closure reactions. The Ullmann coupling reaction of the biaryl diphosphine dioxides is featured by highlyefficient central-to-axial chirality transfer with diastereomeric excess >99%. This substrate-directed diastereomeric biaryl coupling reaction is unprecedented for the preparation
Synthesis of Novel Diastereomeric Diphosphine Ligands and Their Applications in Asymmetric Hydrogenation Reactions
作者:Liqin Qiu、Jianying Qi、Cheng-Chao Pai、Shusun Chan、Zhongyuan Zhou、Michael C. K. Choi、Albert S. C. Chan
DOI:10.1021/ol026817+
日期:2002.12.1
Diastereomeric biaryl diphosphine ligands 10 and 11 with added chiral centers on the backbone were synthesized. Substrate-directed asymmetricsynthesis occurred in the coupling step of the preparation of the diastereomeric diphosphine oxides. The diastereomeric diphosphine oxides were easily separated by column chromatography with silica gel. Ruthenium catalysts containing these ligands were highly effective
Catalytic Asymmetric Silane Alcoholysis: Practical Access to Chiral Silanes
作者:Darby R. Schmidt、Steven J. O'Malle、James L. Leighton
DOI:10.1021/ja0283201
日期:2003.2.1
A new asymmetric synthesis of chiral silanes has been developed. Chiral phosphine-modified copper complexes catalyze the alcoholysis of prochiral dihydrosilanes with good to excellent stereoselectivity at silicon. The application of this methodology to the tandem silylformylation-allylsilylation of alkynes has been demonstrated.
The present invention provides compounds of the formula
wherein R is optionally substituted lower alkyl, cycloalkyl or aryl; R′ is alkyl or aryl; n is zero or an integer of 1 or 2; or an enantiomer thereof; or an enantiomeric mixture thereof.
The compounds of formula (I) are bridged C
2
-symmetric biphenyldiphosphine analogs and, thus, may be employed as ligands to generate chiral transition metal catalysts which may be applied in a variety of asymmetric reactions. The compounds of the present invention are easily accessible in high diastereomeric and optical purity according to the methods disclosed herein.
A Diastereodivergent and Enantioselective Approach to <i>syn</i>- and <i>anti</i>-Diamines: Development of 2-Azatrienes for Cu-Catalyzed Reductive Couplings with Imines That Furnish Allylic Amines
作者:Pengfei Zhou、Xinxin Shao、Steven J. Malcolmson
DOI:10.1021/jacs.1c07707
日期:2021.9.1
catalytic enantioselective synthesis of allylic amines. Herein, we demonstrate their promise by a diastereodivergent synthesis of syn- and anti-1,2-diamines through their Cu–bis(phosphine)-catalyzed reductivecouplings with imines. With Ph-BPE as the supporting ligand, anti-diamines are obtained (up to 91% yield, >20:1 dr, and >99:1 er), and with the rarely utilized t-Bu-BDPP, syn-diamines are generated (up