Rh(III)-Catalyzed Regio- and Chemoselective [4 + 1]-Annulation of Azoxy Compounds with Diazoesters for the Synthesis of 2<i>H</i>-Indazoles: Roles of the Azoxy Oxygen Atom
作者:Zhen Long、Zhigang Wang、Danni Zhou、Danyang Wan、Jingsong You
DOI:10.1021/acs.orglett.7b00631
日期:2017.6.2
tandem C–H alkylation/intramolecular decarboxylative cyclization of azoxy compounds with diazoesters for the synthesis of 3-acyl-2H-indazoles is disclosed. The azoxy instead of the azo group enables a distinct approach for cyclative capture, leading to a [4 + 1]-annulation rather than a classic [4 + 2] manner. The azoxy oxygen atom is traceless after annulation, and further removal from the product is
A convenient protocol for highly selective delivery of azoxybenzenes from reduction of nitrobenzenes was developed by utilizing a coppercatalyst. A variety of functional groups and substitution were well tolerated.
Aryliminodimagnesium Reagents. XV. Condensation with Nitrobenzene. Formation of Unsymmetrical Azobenzenes Favored by Long-Chain<i>p</i>-Alkoxy-Substituted Reagents
作者:Masao Okubo、Koji Matsuo、Akira Yamauchi
DOI:10.1246/bcsj.62.915
日期:1989.3
In the reaction of p-MeC6H4N(MgBr)2 with p-alkoxynitrobenzene, no effect of alkoxyl chain length on the relative yields of azoxy and azo products was observed. In contrast, in the reaction of p-alkoxy-C6H4N(MgBr)2 with p-nitrotoluene, C12- and C18-alkoxyl chains led to the corresponding unsymmetrical azobenzenes in unexpectedly high yields. This result, arising from efficient condensation and deoxygenation processes, was explained in terms of cooperation of reagent molecules through their aggregation assisted by a novel tying effect of their long chains.
Azoxyarenes are among important scaffolds in organic molecules. Direct oxidativecoupling of primary anilines provides a concise fashion to construct them. However, whether these scaffolds can be prepared from secondary N-alkylanilines is not well explored. Here, we present a catalytic selective oxidativecoupling of secondary N-alkylaniline to afford azoxyarene with tungsten catalyst under mild conditions
report a new nitrogen-directed Rh(III)-catalyzed C(sp2)–H bond functionalization of N-nitrosoanilines and azoxybenzenes with maleimides as a coupling partner, in which the olefination/alkylation process can be finely controlled at room temperature by variation of the reaction conditions. This method shows excellent functional group tolerance, and presents a mild access to the resulting olefination/alkylation