New developments in the synthesis of heterotopic atropisomeric diphosphines via diastereoselective aryl coupling reactions
摘要:
The new heterotopic atropisomeric diphosphine (R)-5,6-benzo-2,2'-bis(diphenylphosphino)-4',5',6'-trimethylbiphenyl has been prepared. The key step of this synthesis is a diastereoselective intramolecular aryl-aryl coupling reaction via oxidation of a suitable, chiral diarylcuprate. The catalytic properties of the diphosphine in ruthenium promoted hydrogenations of model substrates and in rhodium promoted 1,4-additions of boronic acids to alpha,beta-unsaturated ketones are fully comparable to those of reference ligands such as BINAP. This seems to indicate that C-2-symmetry is not a structural prerequisite for atropisomeric chiral diphosphines to obtain high enantio selectivities in 1,4-addition reactions as well as in hydrogenation reactions. (C) 2004 Elsevier Ltd. All rights reserved.
The present invention is directed to novel chiral diphosphines (R) or (S) and their use as optically active ligands for preparing diphosphine-metal complexes. The present invention also relates to a diphosphine-metal complex containing the chiral diphosphine (R) or (S), and to the use of the diphosphine-metal complex as a catalyst in a method for asymmetric catalysis of an unsaturated compound having a functional group. .
Enantiopure synthesis of dihydrobenzo[1,4]-oxazine-3-carboxylic acids and a route to benzoxazinyl oxazolidinones
作者:Rajesh Malhotra、Tushar K. Dey、Sourav Basu、Saumen Hajra
DOI:10.1039/c4ob02475c
日期:——
A two step protocol is developed for the enantiopure synthesis of dihydrobenzoxazine-3-carboxylic acids via RuPhos Palladacycle-catalyzed aminoarylation of β-(2-bromoaryloxy)amino acids.
Regioselective Aromatic Perfluoro-<i>tert</i>-butylation Using Perfluoro-<i>tert</i>-butyl Phenyl Sulfone and Arynes
作者:Zhiqiang Wei、Lixian Wen、Kaidi Zhu、Qian Wang、Yanchuan Zhao、Jinbo Hu
DOI:10.1021/jacs.2c10479
日期:2022.12.7
synthetic protocol to realize aromatic perfluoro-tert-butylation. The key to the success is the identification of PFtB phenyl sulfone as a new source of PFtB anion, which reacts with arynes in a highly regioselective manner to afford perfluoro-tert-butylated arenes in high yields. The application of the method is demonstrated by the preparation of sensitive 19F-labeled NMRprobes with an extraordinary resolving
Nickel-Catalyzed Atroposelective Cross-Electrophile Coupling of Aryl Halides: A General and Practical Route to Diverse MOP-Type Ligands
作者:Raphael S. Kim、Lebogang O. Kgoadi、Jacob C. Hayes、Derek P. Rainboth、Catherine M. Mudd、Glenn P. A. Yap、Donald A. Watson
DOI:10.1021/jacs.4c04608
日期:2024.7.3
We report a highly cross- and atroposelective coupling between ortho-(chloro)arylphosphine oxides and ortho-(bromo)aryl ethers. This previously unknown asymmetric nickel-catalyzed reaction offers a direct route to highly enantioenriched axially chiral biaryl monophosphine oxides that are difficult to access by other means. These products can be readily reduced to generate chiral MOP-type ligands bearing