A Study of the Reactions of 3‐Bromopropenals with Anilines for the Synthesis of α‐Bromo Enaminones
作者:Sundaram Suresh、Prakash Bhimrao Patil、Pao‐Hsing Yu、Chia‐Chi Fang、Yin‐Zhi Weng、Veerababurao Kavala、Ching‐Fa Yao
DOI:10.1002/adsc.202100779
日期:2021.11.9
The reactions proceed via the p-toluenesulfonic acid monohydrate (TsOH ⋅ H2O) catalyzed reactions of 3-bromopropenals with anilines in dimethyl sulfoxide (DMSO) and does not require an external brominating agent. The chemoselective 1,2-addition was accomplished by employing aniline with a sterically hindered electron-withdrawing group attached at the ortho-position. In addition, the reactions involving
Divergent NHC-Catalyzed Oxidative Transformations of 3-Bromoenal: Selective Synthesis of 2<i>H</i>-Pyran-2-ones and Chiral Dihydropyranones
作者:Gang Wang、Xia Chen、Gaohan Miao、Weijun Yao、Cheng Ma
DOI:10.1021/jo400950j
日期:2013.6.21
A selectivesynthesis of either 2H-pyran-2-ones (4) or chiral dihydropyranones (6) from the same substrates of 3-bromoenals and 1,3-dicarbonyl compounds upon oxidative N-heterocyclic carbene catalysis is presented. It is shown that the oxidative transformation of 3-bromoenals under NHC catalyst can be well controlled to proceed through two pathways, i.e., elimination of reducible β-bromide or by an
An N-heterocyclic-carbene-catalyzed asymmetric formal [3+2] annulation reaction of isatin N-Boc ketimines (Boc = tert-butyloxycarbonyl) and 3-bromoenals was developed for the construction of spiro[indoline-3,2′-pyrrole] derivatives with one quaternary chiral center in good yields (up to 81 % yield) with excellent enantioselectivity (up to 99 % ee).
Construction of [2,5]-Furanophanes by Carbene-Mediated Alkynyl Migration Cyclization
作者:Qiu Shi、Yang Chen、Tongxiang Cao、Shifa Zhu
DOI:10.1021/acs.orglett.2c03185
日期:2022.11.11
Heterophanes are widely found in natural products and drug molecules. Herein, an efficient method for the construction of [2,5]-furanophanes with differentring types and ringsizes was developed. This method is carried out with furan-free precursor throughintramolecular carbene-mediated alkynyl migration and tandem cyclization strategy. In addition, a series of tetrafuran structures can be obtained by oxidative
An efficient cobalt-catalyzed tandemone-pot method has been developed for the synthesis of polysubstituted imidazo[1,5-a]-N-heteroaromatics. The method involves Knoevenagel condensation followed by cobalt-catalyzed direct alkenylation to give the desired polysubstituted imidazo[1,5-a]pyridines and imidazo[1,5-a]isoquinolines in a one-pot manner. This method exhibits a broad substrate scope, provides
开发了一种高效的钴催化串联一锅法合成多取代的咪唑并[1,5 - a ]-N-杂芳烃。该方法涉及 Knoevenagel 缩合,然后是钴催化的直接烯基化,以一锅方式得到所需的多取代咪唑并[1,5- a ]吡啶和咪唑并[1,5 - a ]异喹啉。这种方法表现出广泛的底物范围,提供中等至良好(39-74%)的产量,并且可以放大到克级。