or amides can be synthesized in a single step by a carbonylative coupling of α-chloroimines with alcohols or amines under Pd-catalysis. The methodology has been also applied to the preparation of heteroaryl acetic acid derivatives starting from chloromethyl heteroaromatic rings containing a CN double bond. The in situ generation of a β-imino acylpalladium species has been proposed as a key step for
A simple and efficient approach has been developed for the synthesis of imidazo[1,5-a]pyridines using the elemental sulfur mediated sequential dual oxidative Csp3–H amination of 2-pyridyl acetates and amines under metal- and peroxide-free conditions. Broad substrate scope, operational simplicity and gram-scale ability make this chemistry very practical.
已经开发了一种简单有效的方法,用于在无金属和无过氧化物的条件下,使用元素硫介导的乙酸2-吡啶酯和胺的连续双氧化Csp 3 -H胺化来合成咪唑并[1,5- a ]吡啶。广泛的底物范围,操作简便和克级能力使这种化学非常实用。
Iodine-Mediated Oxidative Cyclization of 2-(Pyridin-2-yl)acetate Derivatives with Alkynes: Condition-Controlled Selective Synthesis of Multisubstituted Indolizines
作者:Lisheng He、Yuzhu Yang、Xiaolan Liu、Guangyan Liang、Chunyan Li、Daoping Wang、Weidong Pan
DOI:10.1055/s-0039-1690229
日期:2020.2
An iodine-mediated oxidative cyclization reaction between 2-(pyridin-2-yl)acetate derivatives and different alkynes has been developed, which provides regioselective and chemoselective syntheses of multiply substituted indolizines under modified reaction conditions. Plausible mechanisms have been proposed to explain the selective syntheses of indolizines. This protocol can be also applied to the stepwise
Metal-Free Aminothiation of Alkynes: Three-Component Tandem Annulation toward Indolizine Thiones from 2-Alkylpyridines, Ynals, and Elemental Sulfur
作者:Zhengwang Chen、Pei Liang、Fan Xu、Zhen Deng、Lipeng Long、Guotian Luo、Min Ye
DOI:10.1021/acs.joc.9b01802
日期:2019.10.4
A metal-free three-component annulation reaction for the synthesis of indolizine thiones via tandem C-C/C-N/C-S bondformation was developed. Various 2-alkylpyridines with aromatic ynals and elemental sulfur proceeded smoothly under catalyst-free conditions, and the desired products were obtained in moderate to excellent yields.
catalyzed synthesis of indolizine-1-carboxylates through oxidative CC and CN bondformations by the reaction of 2-pyridyl acetates with alkynes and alkenes without metal, oxidant, and base. This procedure is compatible with a broad range of functional groups in both alkynes and alkenes with good yields. The reaction proceeds through a tandem CC bondformation followed by an intramolecular cyclization