chemoselective double annulation of α-trifluoromethylated isocyanides with o-acylaryl isocyanides has been developed. This new reaction provides a rapid, efficient, and complete atom-economic strategy for the synthesis of trifluoromethylated oxadiazino[3,2-a]indoles in a single operation from readily available starting materials. Isocyanide insertion into C═O double bonds is disclosed for the first
已经开发出空前的α-三氟甲基化异氰酸酯与邻酰基芳基异氰酸酯的化学选择性双环。该新反应提供了快速,有效和完整的原子经济策略,可通过一次操作从容易获得的起始原料合成三氟甲基化的恶二嗪并[3,2- a ]吲哚。由18 O-标记实验的结果表明,异氰酸酯首次插入C = O双键。提出了这种多米诺反应的机制,其中包括两种不同异氰酸酯的化学选择性异二聚化,然后是吲哚-2,3-环氧化物的形成和重排。
Silver-Catalyzed Chemoselective [4+2] Annulation of Two Isocyanides: A General Route to Pyridone-Fused Carbo- and Heterocycles
silver‐catalyzed chemoselective [4+2] annulation of aryl and heteroaryl isocyanides with α‐substituted isocyanoacetamides was developed for the facile and efficient synthesis of 2‐aminoquinolones, naphthyridines, and phenanthrolines. A mechanism for this multistep domino reaction is proposed on the basis of a 13C‐labeling experiment, according to which an unprecedented chemoselective heterodimerization
Silver-Catalyzed [3+2] Cycloaddition of Azomethine Ylides with Isocyanides for Imidazole Synthesis
作者:Zhongyan Hu、Jinhuan Dong、Xianxiu Xu
DOI:10.1002/adsc.201700447
日期:2017.10.25
silver-catalyzed aerobic oxidative [3+2] cycloaddition of azomethineylides with aryl or heteroaryl isocyanides has been developed. The reaction represents a novel protocol for the efficient and practical synthesis of 1,2-diarylimidazoles bearing a broad range of substituents in good to excellent yields under mild conditions. The practicability of this cycloaddition was shown by a gram-scale synthesis
A facile method for the synthesis of 3-substituted 3H-indol-3-ols has been developed. Thus, 2-isocyanophenyl ketones are allowed to react with various Grignardreagents to give the corresponding desired indolol derivatives in generally fair to good yields. The formation of 3-aryl-2,3-dimethylindolin-3-ols by the reaction of 2-isocyanobenzophenones with 2 M amounts of methylmagnesium bromide is also
The reaction of α-substituted 2-isocyanostyrenes, which could be readily prepared from commercially available 2-aminophenyl ketones or 2-aminobenzonitriles, with sulfur in the presence of a catalytic amount of selenium proceeded smoothly to give the corresponding 2-isothiocyanatestyrenes. The latter spontaneously underwent the electrocyclic reaction to afford 4-substituted quinoline-2(1H)-thiones in one-pot with isolated yields ranging from 37 to 91%.