Asymmetric Allylboration of Ketones Catalyzed by Chiral Diols
作者:Sha Lou、Philip N. Moquist、Scott E. Schaus
DOI:10.1021/ja0651308
日期:2006.10.1
Chiral BINOL-derived diols catalyze the enantioselective asymmetricallylboration of ketones. The reaction requires 15 mol % of 3,3‘-Br2-BINOL as the catalyst and allyldiisopropoxyborane as the nucleophile. The reaction products are obtained in good yields (76−93%) and high enantiomeric ratios (95:5−99.5:0.5). High diastereoselectivities (dr ≥ 98:2) and enantioselectivities (er ≥ 98:2) are obtained
Catalytic Asymmetric Allylation of Ketones and a Tandem Asymmetric Allylation/Diastereoselective Epoxidation of Cyclic Enones
作者:Jeung Gon Kim、Karen M. Waltz、Iliana F. Garcia、David Kwiatkowski、Patrick J. Walsh
DOI:10.1021/ja047758t
日期:2004.10.1
titanium tetraisopropoxide, BINOL, 2-propanol additive, and tetraallylstannane as allylating agent. A variety of ketone substrates, including acetophenone derivatives and alpha,beta-unsaturated cyclic enones, reacted to form tertiary homoallylic alcohols in good yields (67-99%) and with high levels of enantioselectivity (generally >80%). A novel one-pot enantioselective allylation/diastereoselective
Design and Synthesis of Modular Oxazoline Ligands for the Enantioselective Chromium-Catalyzed Addition of Allyl Bromide to Ketones
作者:Jeremie J. Miller、Matthew S. Sigman
DOI:10.1021/ja068915m
日期:2007.3.1
By systematically evaluating ligand diastereomers using a modular oxazoline template, a new ligand has been identified leading to the discovery of the first example of a chromium-catalyzed enantioselective allylation of ketones using allylic bromides.
A Simple, Reliable, Catalytic Asymmetric Allylation of Ketones
作者:Karen M. Waltz、Jason Gavenonis、Patrick J. Walsh
Highly Concentrated Catalytic Asymmetric Allylation of Ketones
作者:Alfred J. Wooten、Jeung Gon Kim、Patrick J. Walsh
DOI:10.1021/ol062264h
日期:2007.2.1
We report the catalytic asymmetric allylation of ketones under highly concentrated reaction conditions with a catalyst generated from titanium tetraisopropoxide and BINOL (1:2 ratio) in the presence of isopropanol. This catalyst promotes the addition of tetraallylstannane to a variety of ketones to produce tertiary homoallylic alcohols in excellent yield (80-99%) with high enantioselectivities (79-95%). The resulting homoallylic alcohols can also be epoxidized in situ using tert-butyl hydroperoxide (TBHP) to afford cyclic epoxy alcohols in high yield (84-87%).