Enantioselective Organo-Photocatalysis Mediated by Atropisomeric Thiourea Derivatives
作者:Nandini Vallavoju、Sermadurai Selvakumar、Steffen Jockusch、Mukund P. Sibi、Jayaraman Sivaguru
DOI:10.1002/anie.201310940
日期:2014.5.26
this, organo‐photocatalysts that are based on atropisomericthioureas and display lower excited‐state energies than the reactive substrates have been developed. These photocatalysts were found to be efficient in promoting the [2+2] photocycloaddition of 4‐alkenyl‐substituted coumarins, which led to the corresponding products with high enantioselectivity (77–96 % ee) at low catalyst loading (1–10 mol %)
[EN] FORMYLATION PROCESS FOR PREPARING AROMATIC FORMAMIDES<br/>[FR] PROCESSUS DE FORMYLATION POUR LA PRÉPARATION DE FORMAMIDES AROMATIQUES
申请人:RHODIA OPERATIONS
公开号:WO2015192282A1
公开(公告)日:2015-12-23
The present invention mainly pertains to a catalytic process for preparing a formamide,comprising reacting a formic acid ester with an aromatic amine carrying at least one electron withdrawing group in the presence of a catalyst of fluorine-containing sulfonimide metal salt.
Comparative Measure of the Electronic Influence of Highly Substituted Aryl Isocyanides
作者:Alex E. Carpenter、Charles C. Mokhtarzadeh、Donald S. Ripatti、Irena Havrylyuk、Ryo Kamezawa、Curtis E. Moore、Arnold. L. Rheingold、Joshua S. Figueroa
DOI:10.1021/ic5030845
日期:2015.3.16
substituted aryl isocyanides on transitionmetal centers, a series of C4v-symmetric Cr(CNR)(CO)5 complexes featuring various alkyl, aryl, and m-terphenyl substituents have been prepared. A correlation between carbonyl-ligand 13C1H} NMR chemical shift (δCO) and calculated Cotton–Kraihanzel (C–K) force constant (kCO) is presented for these complexes to determine the relative changes in isocyanide σ-donor/π-acid
为了评估对过渡金属中心高度取代的芳基异腈的相对电子影响,一系列ç 4 v -对称的Cr(CNR)(CO)5个络合物设有各种烷基,芳基和米-三联苯取代基已被制备。羰基配位体之间的相关性13 13 C 1个H} NMR化学位移(δ CO)和计算出的棉Kraihanzel(C-K)的力常数(ķ CO给出了针对这些配合物的),以确定异氰化物σ-供体/π-酸比率的相对变化,该变化是取代基同一性和样式的函数。对于具有烷基或芳基取代的非氟化芳基异氰化物,在整个系列中观察到有效σ供体/π酸比率的最小变化。此外,具有强电子释放性取代基的芳基异氰化物显示出的电子影响几乎与非氟化烷基异氰化物的电子影响相匹配。多氟化芳基异氰化物配体显示出较低的σ-供体/π-酸比率。然而,相对于非氟化芳基异氰酸酯而言,这种衰减程度并不显着,并且在所有情况下均观察到比CO显着更高的σ-给体/π-酸比率。确定了多氟化芳基异氰化物的
KO<sup><i>t</i></sup>Bu-Promoted Transition-Metal-Free Transamidation of Primary and Tertiary Amides with Amines
作者:Tridev Ghosh、Snehasish Jana、Jyotirmayee Dash
DOI:10.1021/acs.orglett.9b02306
日期:2019.9.6
transamidation of primary and tertiary amides with a range of aryl, heteroaryl, and aliphatic amines using potassium tert-butoxide. The reaction proceeds at roomtemperature under transition-metal-free conditions providing secondary amides in high yields. Moreover, reaction of cyclopropyl amine with tertiary amides proceeds with ring-opening to provide a rapid access to enamides.
Novel bifunctional thiourea–ammonium salt catalysts derived from amino acids: application to highly enantio- and diastereoselective aza-Henry reaction
作者:Hong-Yu Wang、Zhuo Chai、Gang Zhao
DOI:10.1016/j.tet.2013.04.079
日期:2013.6
development of new efficient and easily accessible catalysts has been one of the focuses in asymmetric phase-transfer catalysis. In this paper, a novel class of chiral bifunctional thiourea–ammonium phase-transfercatalysts were synthesized from commercially available α-amino acids. The structural modularity of these catalysts permits facile tunings to achieve optimum results, which was demonstrated