an aromaticaldehyde for use in asymmetric synthesis. The reaction between aromaticaldehydes and aryl or allyl electrophiles with a silylboronate utilizing a chiral copper-N-heterocyclic carbene catalyst and a palladium-bisphosphine catalyst in a synergistic manner occurred with high enantioselectivities to deliver the three-component coupling products, chiral silyl-protected secondary alcohol derivatives
Enantioselective Arylations Catalyzed by Carbohydrate-Based Chiral Amino Alcohols
作者:Ana Dionéia Wouters、Gustavo H. G. Trossini、Hélio A. Stefani、Diogo S. Lüdtke
DOI:10.1002/ejoc.201000113
日期:2010.4
The application of carbohydrate-derived aminoalcohols in the asymmetric arylation of aldehydes by using arylboronic acids as the source of transferable aryl groups is described. The best ligand is derived from the readily available sugar D-xylose and it mediates the addition of a range of arylboronic acids to various aromatic aldehydes in excellent yields and high enantiomeric excesses.
Evaluation of Enantiopure <i>N</i>-(Ferrocenylmethyl)azetidin-2-yl(diphenyl)methanol for Catalytic Asymmetric Addition of Organozinc Reagents to Aldehydes
作者:Min-Can Wang、Qing-Jian Zhang、Wen-Xian Zhao、Xiao-Dan Wang、Xue Ding、Tao-Tao Jing、Mao-Ping Song
DOI:10.1021/jo701943x
日期:2008.1.1
catalytic asymmetric addition of organozinc reagents to aldehydes. The asymmetric ethylation, methylation, arylation, and alkynylation of aldehydes achieved enantioselectivity of up to 98.4%, 94.1%, 99.0%, and 84.6% ee, respectively, in the presence of a catalytic amount of chiral N-(ferrocenylmethyl)azetidin-2-yl(diphenyl)methanol. Our results demonstrated further that the four-membered heterocycle-based
Asymmetric additive-free aryl addition to aldehydes using perhydrobenzoxazines as ligands and boroxins as aryl source
作者:Rebeca Infante、Javier Nieto、Celia Andrés
DOI:10.1039/c1ob05717k
日期:——
A highly efficient enantioselective aryl addition to aldehydes using boroxins as aryl source and conformationally restricted perhydro-1,3-benzoxazines as ligands is reported. Both enantiomeric forms of chiral arylphenylmethanols and 1,1′-disubstituted diarylmethanols are afforded with excellent yields and enantioselectivities using the same ligand by means of an appropriate combination of boroxin and aromatic aldehyde. The enantiocontrol is not significantly influenced by electronic effects or steric hindrance, even with substituted boroxins. Very homogeneous ee's are reached when substituted arylboroxins are employed, without the use of any class of additive or pre-treatment.