Ir‐phosphinomethyl‐oxazoline complexes have been identified as efficient, highlyenantioselective catalysts for the asymmetric hydrogenation of 3,3‐disubstituted allylicalcohols and related homoallylic alcohols. In contrast to other N,Pligand complexes, which require weakly coordinating solvents, such as dichloromethane, these catalysts perform well in more ecofriendly THF or 2‐MeTHF. Their synthetic
Stereospecific Transformations of Alkylboronic Esters Enabled by Direct Boron-to-Zinc Transmetalation
作者:Hao Liang、James P. Morken
DOI:10.1021/jacs.3c01677
日期:2023.5.10
Chiral secondary organoboronic esters, when activated with t-butyllithium, are shown to undergo efficient stereoretentive transmetalation with either zinc acetate or zinc chloride. This reaction provides chiral secondary alkylzinc reagents that are configurationally stable under practical experimental conditions. The organozinc compounds were found to engage in stereospecific reactions with difluorocarbene
Enantioselective Redox-Relay Oxidative Heck Arylations of Acyclic Alkenyl Alcohols using Boronic Acids
作者:Tian-Sheng Mei、Erik W. Werner、Alexander J. Burckle、Matthew S. Sigman
DOI:10.1021/ja402916z
日期:2013.5.8
A general, highly selective asymmetric redox-relay oxidative Heck reaction using achiral or racemic acyclic alkenols and boronic acid derivatives is reported. This reaction delivers remotely functionalized arylated carbonyl products from acyclic alkenol substrates, with excellent enantioselectivity under mild conditions, bearing a range of useful functionality. A preliminary mechanistic investigation suggests that the regioselectivity of the initial migratory insertion is highly dependent on the electronic nature of the boronic acid and more subtle electronic effects of the alkenyl alcohol.
Levene; Marker, Journal of Biological Chemistry, 1935, vol. 110, p. 329,341