报道了用3-丁烯-1-醇对环丙烷甲醛的单步TiX 4介导的Prins型环化反应,以相对立体地构建相对应变的(E)-六氢氧代肟酸酯。将醇转换为3-butyn-1-ol引发了类似的路线,并在九元环内进行了另一个环化反应,从而得到了双环化产物(4,4-二卤代5-芳基氢环戊[ b ]吡喃)。容易将生成的二卤代双卤化物转化为乙烯基卤化物和酮,进一步补充了这种方法的实质。
Metal-free domino Cloke-Wilson rearrangement-hydration-dimerization of cyclopropane carbaldehydes: A facile access to oxybis(2-aryltetrahydrofuran) derivatives
作者:Raghunath Dey、Shruti Rajput、Prabal Banerjee
DOI:10.1016/j.tet.2020.131080
日期:2020.4
demonstrated a metal-free transformation of cyclopropane carbaldehydes to oxybis(2-aryltetrahydrofuran) derivativesvia a domino Cloke-Wilson rearrangement-hydration-dimerization sequence. Commercially inexpensive p-toluene sulfonic acid (PTSA) was used as a Brønsted acid catalyst, and reactions were conducted in an open-flask. Detection of reaction intermediates were carried to get an insight into the
Selective carbene transfer to amines and olefins catalyzed by ruthenium phthalocyanine complexes with donor substituents
作者:Lucie P. Cailler、Andrey P. Kroitor、Alexander G. Martynov、Yulia G. Gorbunova、Alexander B. Sorokin
DOI:10.1039/d0dt04090h
日期:——
Electron-rich ruthenium phthalocyanine complexes were evaluated in carbene transfer reactions from ethyl diazoacetate (EDA) to aromatic and aliphatic olefins as well as to a wide range of aromatic, heterocyclic and aliphatic amines for the first time. It was revealed that the ruthenium octabutoxyphthalocyanine carbonyl complex [(BuO)8Pc]Ru(CO) is the most efficient catalyst converting electron-rich
富电子钌酞菁配合物是首次从重氮乙酸乙酯(EDA)到芳香族和脂肪族烯烃以及各种芳香族,杂环和脂肪族胺的卡宾转移反应中进行评估的。结果表明,八丁氧基酞菁钌羰基络合物[(BuO)8Pc] Ru(CO)是最有效的催化剂,在低催化剂负载和几乎等摩尔的底物条件下,可以将高电子含量和电子贫乏的芳族烯烃转化为环丙烷衍生物,并具有高收率(通常为80–100%)和高TON(最高为1000)。 / EDA比。该催化剂在卡宾插入胺N–H键中显示出罕见的效率。使用0.05摩尔%的催化剂负载量,高胺浓度(1M)和1.1当量。在EDA的作用下,许多结构不同的胺被选择性地转化为单取代的甘氨酸衍生物,其定量收率和周转数均达到2000。高选择性,大底物范围,低催化剂载量和实际反应条件[[BuO)8 Pc ] Ru(CO)是卡宾插入胺中最有效的催化剂。
Accessing Complex Tetrahydrofurobenzo-Pyran/Furan Scaffolds <i>via</i> Lewis-Acid Catalyzed Bicyclization of Cyclopropane Carbaldehydes with Quinone Methides/Esters
and tetrahydrofurobenzofuran systemsvia an in situ ring-expansion of the cyclopropane carbaldehydes followed by a [2 + n] cycloaddition with the quinone derivatives. The transformation not only unveils a new reaction mode of cyclopropane carbaldehydes with quinone methides/esters, but also promotes a step-efficient diastereoselective route to the sophisticatedly fused oxygen tricycles that can be
在这里,我们报告了四氢呋喃苯并吡喃和四氢呋喃苯并呋喃体系的直接一锅合成方法,方法是通过环丙烷甲醛的原位扩环,然后与醌衍生物进行 [2 + n ] 环加成。该转化不仅揭示了环丙烷甲醛与醌甲基化物/酯的新反应模式,而且还促进了一种高效的非对映选择性路线,可以进一步脱氢得到有价值的二氢-2H-呋喃[2 ,3- b ]铬烯框架。
Chiral BINOL-based borate counterions: from cautionary tale on anion stability to enantioselective Cu-catalyzed cyclopropanation
作者:Anthony Labelle、Bruce A. Arndtsen
DOI:10.1039/d2cc05924j
日期:——
Studies on a new type of chiral BINOL-based boron counterion highlights its ability to rearrange under the reaction conditions to create a ligand that can be used in the copper-catalyzed cyclopropanation of alkenes.
cis-Enhanced cyclopropanation catalysts: reaction chemistry of three isomers of Rh2[N(C6H5)COCH3]4
作者:Cassandra T. Eagle、David Farrar、Grant N. Holder、Michelle L. Hatley、Shirley L. Humphrey、Elizabeth V. Olson、Maria Quintos、Joseph Sadighi、Tom Wideman
DOI:10.1016/s0040-4039(03)00222-3
日期:2003.3
The catalytic activities of three structural isomers of Rh-2[N(C6H5)COCH3](4) in cyclopropanation reactions were surveyed. These studies showed cis cyclopropanation selectivity with bulky alkenes for 2,2-cis- and 2,2-trans-Rh-2[N(C6H5)COCH3](4). (C) 2003 Elsevier Science Ltd. All rights reserved.