在六个或七个合成步骤中制备了一系列胍鎓催化剂,并用于21-86%ee的甘氨酸Schiff碱的相转移烷基化,以及85-94%ee的一些查耳酮的相转移环氧化。使用分光光度法,对于某些催化剂,确定了DMSO中p K a值在13.2–13.9范围内,从而突出了相对于非手性四甲基胍的碱度增加(p K a= 13.0),提出了一种以质子化的胍鎓离子作为相转移催化剂的机理。研究了使用两种催化剂在迈克尔加成反应中添加亲核试剂,发现两者都是有效的催化剂。在这些反应中抗衡离子作用是明显的,但是没有观察到对映选择性。
A base-controlled chemoselective transfer hydrogenation of α,β-unsaturated ketones catalyzed by [IrCp*Cl<sub>2</sub>]<sub>2</sub> with 2-propanol
作者:Shu-jie Chen、Guo-ping Lu、Chun Cai
DOI:10.1039/c5ra00484e
日期:——
A simple homogeneous catalyst system based on commercially available [IrCp*Cl2]2 has been developed for the transfer hydrogenation of α,β-unsaturated ketones.
[EN] A METHOD FOR PREPARING SULFUR-CONTAINING COMPOUNDS<br/>[FR] PROCÉDÉ POUR LA PRÉPARATION DE COMPOSÉS CONTENANT DU SOUFRE
申请人:ROYAL COLLEGE OF SURGEONS IE
公开号:WO2010066450A1
公开(公告)日:2010-06-17
The invention provides a method for preparing sulfur-containing compounds, the method comprising reacting a donor compound comprising at least one sulfur having at least one lone pair of electrons, with an acceptor compound; wherein the reaction occurs in the presence of an amine, optionally an amine catalyst, capable of activating the sulfur having at least one lone pair of electrons; and wherein the reaction occurs via the formation of an transient intermediate species, optionally a transient intermediate species, between the amine, optionally the amine catalyst and the donor compound; and wherein the donor compound is selected from the group consisting of a sulfurous acid, a sulfenic acid and a sulfinic acid or a salt, ester or amide of a sulfurous acid, a sulfenic acid and a sulfinic acid. The invention also provides sulfur-containing compounds of the formula: wherein R is selected from: (a) 1 -(4-Nitro-phenyl)-3-oxo-3-phenyl-propane; (b) 2-(3-Methyl-4-nitro-isoxazol-5-yl)-1 -phenyl-ethane; (c) 1-(4-Methoxy-phenyl)-2-(3-methyl-4-nitro-isoxazol-5-yl)-ethane; (d) 2-(3-Methyl-4-nitro-isoxazol-5-yl)-1-(4-nitro-phenyl)-ethane; (e) 1-(4-Fluoro-phenyl)-2-(3-methyl-4-nitro-isoxazol-5-yl)-ethane; (f) 1 -(4-Chloro-phenyl)-2-(3-methyl-4-nitro-isoxazol-5-yl)-ethane; and (g) 3-Oxo-cyclohexane. Finally, the invention provides use of chiral sulfur-containing compounds obtainable by the above-mentioned method or chiral sulfur-containing compounds as mentioned above for the resolution of racemic mixtures of amines.
Gold-Catalyzed Hydroamination of Propargylic Alcohols: Controlling Divergent Catalytic Reaction Pathways To Access 1,3-Amino Alcohols, 3-Hydroxyketones, or 3-Aminoketones
作者:Victor Laserna、Michael J. Porter、Tom D. Sheppard
DOI:10.1021/acs.joc.9b00988
日期:2019.9.20
Alternatively, by using a catalytic quantity of aniline, 3-hydroxyketones can be obtained in high yield directly from propargylic alcohols. Further manipulation of the reaction conditions enables the selective formation of 3-aminoketones via a rearrangement/hydroamination pathway. The utility of the new chemistry was exemplified by the one-pot synthesis of a selection of N-arylpyrrolidines and N-arylpiperidines
Addition with α,β unsaturated carbonyl compounds gives 1,5 dicarbonyl products. This method is very convenient and the compounds obtained can easily be separated. We assume that the role of the salt in these reactions is to activate the silicon atom by anionic coordination to form a pentacoordinatedsilicon intermediate.
The Use of α-Trimethylsilyl-α,β-Unsaturated Ketones as 1-Acylethenyl Anion Synthon
作者:Kozo Matsumoto、Koichiro Oshima、Kiitiro Utimoto
DOI:10.1246/cl.1994.1211
日期:1994.7
Treatment of α-trimethylsilyl-α,β-unsaturated ketones with tetrabutylammonium fluoride in the presence of aldehydes provided α-(1-hydroxyalkyl)-α,β-unsaturated ketones in good yields. The reaction proceeded via allenolate. The new method was successfully applied to a synthesis of α-(1-hydroxyalkyl)-α,β-unsaturated esters from α-trimethylsilyl-α,β-unsaturated esters.