A Highly Efficient Pd(PPh<sub>3</sub>)<sub>4</sub>-Catalyzed Suzuki Cross-Coupling Method for the Preparation of 2-Nitrobiphenyls from 1-Chloro-2-nitrobenzenes and Phenylboronic Acids
作者:Vijayaragavan Elumalai、Alexander H. Sandtorv、Hans-René Bjørsvik
DOI:10.1002/ejoc.201501487
日期:2016.3
A simple and efficientmethod for Suzuki cross-coupling of highly substituted and congested 1-chloro-2-nitrobenzene with phenylboronic acid was developed, investigated, and optimized. The reaction conditions comprises a mixture of MeOH and water (4:1) as the reaction medium, readily available and cheap Pd(PPh3)4 as catalyst, sodium carbonate as base, and microwave heating, which affords a fast reaction
The N-alkyl-2,7-dihalocarbazole as the main product was formed by the reaction of 4,4'-dihalo-2-nitrobiphenyl with aromatic nitro compound and trialkyl phosphite. The presence and crucial role of aromatic nitro compound causes simultaneous carbazole ring closure and N-alkylation unlike the Ca-dogan ring closure where non-alkylated carbazole is formed as a main product. In addition, the mixture of aromatic nitro compound and trialkyl phosphite was found to be a possible N-alkylating agent for heterocycles, such as carbazole or indole. (C) 2012 Elsevier Ltd. All rights reserved.
Le Fevre; Turner, Journal of the Chemical Society, 1926, p. 2046