A Novel Axially Chiral 2,2‘-Bipyridine N,N‘-Dioxide. Its Preparation and Use for Asymmetric Allylation of Aldehydes with Allyl(trichloro)silane as a Highly Efficient Catalyst
摘要:
[GRAPHICS]New axially chiral 2,2'-bipyridine N,N'-dioxides were obtained by a new method that does not involve any procedures for the separation of enantiomers. One of the dioxides, (R)-3,3'-bis(hydroxymethyl)-6,6'-diphenyl-2,2'-bipyridine N,N-dioxide, exhibited extremely high catalytic activity for the asymmetric allylation of aldehydes with allyl(trichloro)silane. The allylation of aromatic aldehydes proceeded in the presence of 0.01 or 0.1 mol % of the dioxide catalyst to give the corresponding homoallyl alcohols of up to 98% ee.
A Novel Axially Chiral 2,2‘-Bipyridine N,N‘-Dioxide. Its Preparation and Use for Asymmetric Allylation of Aldehydes with Allyl(trichloro)silane as a Highly Efficient Catalyst
摘要:
[GRAPHICS]New axially chiral 2,2'-bipyridine N,N'-dioxides were obtained by a new method that does not involve any procedures for the separation of enantiomers. One of the dioxides, (R)-3,3'-bis(hydroxymethyl)-6,6'-diphenyl-2,2'-bipyridine N,N-dioxide, exhibited extremely high catalytic activity for the asymmetric allylation of aldehydes with allyl(trichloro)silane. The allylation of aromatic aldehydes proceeded in the presence of 0.01 or 0.1 mol % of the dioxide catalyst to give the corresponding homoallyl alcohols of up to 98% ee.
Metal-free C–H alkylation of heteroarenes with alkyltrifluoroborates: a general protocol for 1°, 2° and 3° alkylation
作者:Jennifer K. Matsui、David N. Primer、Gary A. Molander
DOI:10.1039/c7sc00283a
日期:——
A photoredox-catalyzed C–H functionalization of heteroarenes using a variety of primary, secondary, and tertiary alkyltrifluoroborates is reported. Using Fukuzumi's organophotocatalyst and a mild oxidant, conditions amenable for functionalizing complex heteroaromatics are described, providing a valuable tool for late-stage derivatization. The reported method addresses the three major limitations of
据报道,使用各种伯,仲和叔烷基三氟硼酸酯进行光氧化还原催化的杂芳烃的CH官能化。描述了使用Fukuzumi的有机光催化剂和温和的氧化剂,适合于功能化复杂杂芳族化合物的条件,为后期衍生化提供了有价值的工具。报告的方法解决了先前报道的光氧化还原介导的Minisci反应的三个主要局限性:(1)使用超化学计量的自由基前体,(2)反复选择性,以及(3)引入昂贵的光催化剂。另外,使用了许多前所未有的复杂烷基,从而增加了Minisci化学可利用的化学空间。为了展示后期功能化中的应用程序,合成了奎宁和喜树碱类似物。最后,进行了NMR研究以提供合理的杂芳基活化作用,该活化作用允许使用单当量的自由基前体,并且还提高了区域选择性。因此,在酸催化剂和BF 3的存在下观察到1 H和13 C NMR观察到独特的杂芳基物质。
Visible-light-mediated photoredox decarbonylative Minisci-type alkylation with aldehydes under ambient air conditions
Molybdenum(II) Complexes with α‐Diimines: Catalytic Activity in Organic and Ionic Liquid Solvents
作者:Marta S. Saraiva、Carla D. Nunes、Vítor Félix、Ana P. C. Ribeiro、Carlos Nieto Castro、Maria José Calhorda
DOI:10.1002/ejic.201800700
日期:2018.9.23
The new [MoX(η3‐C3H5)(CO)2(α‐diimine)] complexes with: (i) X = Br or triflate and α‐diimine = 1,10‐phenanthroline (phen) and dipyridophenazine (dppz); and (ii) X = Br and α‐diimine = phen and dppz, with several substituents, are synthesized and characterized. The structures of [MoBr(η3‐C3H5)(CO)2(Cl‐phen)] and [Mo(CF3SO3)(η3‐C3H5)(CO)2(dppz)] are determined by using single‐crystal X‐ray diffraction
新的[MOX(η 3 -C 3 H ^ 5)(CO)2(α-二亚胺)]配合物的:(ⅰ)X = Br或三氟甲磺酸酯和α二亚胺= 1,10-菲咯啉(phen)的和二吡啶并( dppz); (ii)合成并表征了X = Br和α-diimine= phen和dppz,带有多个取代基。[MOBr(η的结构3 -C 3 H ^ 5)(CO)2(CL-phen)的]和[沫(CF 3 SO 3)(η 3 -C 3 H ^ 5)(CO)2(dppz)]是通过使用单晶X射线衍射确定的。在二氯甲烷中几种烯烃的均相催化环氧化中测试了2,3'和2,2'-联吡啶基(bpy)的这三种配合物及其两个具有Me和t Bu取代基的衍生物,通常显示出对各个烯烃的良好选择性。环氧和相对较低的TOF。首次在某些室温离子液体(RTIL)中也进行了其中一些催化剂对顺式环辛烯的氧化反应。在[MOBr(η存在3 -C 3 H ^ 5)(CO
Iridium-Catalyzed Transfer Hydrogenation of 1,10-Phenanthrolines using Formic Acid as the Hydrogen Source
The iridium‐catalyzed highly regioselective transfer hydrogenation of a variety of 2‐substituted and 2,9‐disubstituted 1,10‐phenanthrolines under mild conditions with formic acid as the hydrogen source is described. In the presence of a catalytic amount of the iridium complex [Cp*IrCl2]2, the transfer hydrogenation proceeded smoothly in 1,4‐dioxane under ligand‐free conditions, exclusively leading
A New Synthetic Route to Enantiomerically Pure Axially Chiral 2,2‘-Bipyridine <i>N,N</i><i>‘</i>-Dioxides. Highly Efficient Catalysts for Asymmetric Allylation of Aldehydes with Allyl(trichloro)silanes
作者:Toyoshi Shimada、Asato Kina、Tamio Hayashi
DOI:10.1021/jo0300800
日期:2003.8.1
Newaxiallychiral 2,2'-bipyridine N,N'-dioxides 1 were obtained in an enantiomerically pure form by way of cyclic diesters 6 or 7 which were formed by the esterification of diols 2 with (R)-2,2'-bis(chlorocarbonyl)-1,1'-binaphthalene (5). Epimerization of the kinetic products at the ester formation (R(nap),S(pyr))-6 to the thermodynamically stable isomers (R(nap),R(pyr))-7 was observed in refluxing