Significant facilitation of metal-free aerobic oxidative cyclization of imines with water in synthesis of benzimidazoles

Autor:	Seung Jae Lee, Gee-Sung Chae, Cheol Hong Cheon, Jong Kwan Bin, Yeon Ho Cho, Ye Sol Lee, Yang Joong-Hwan
Rok vydání:	2015
Předmět:	Oxidative cyclization Benzimidazole chemistry.chemical_compound chemistry Nucleophile Metal free Baldwin's rules Organic Chemistry Drug Discovery Organic chemistry Metal catalyst Biochemistry Catalysis
Zdroj:	Tetrahedron. 71:532-538
ISSN:	0040-4020
DOI:	10.1016/j.tet.2014.12.043
Popis:	A simple, convenient, and environmentally benign protocol for the synthesis of benzimidazoles from ortho-phenylenediamines and aldehydes via aerobic oxidation was developed in wet organic solvents. Notably, water significantly accelerated this transformation, which allowed us to achieve this important transformation without the assistance of any metal catalysts and other co-oxidants. Mechanistic studies suggested that water acts as the nucleophilic catalyst for this transformation by the conversion of disfavored 5-endo-trig cyclization of imines to favored 5-exo-tet cyclization via tetrahedral intermediates and the subsequent aerobic oxidation of the resulting benzimidazolines affords benzimidazoles.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::5fb419dc52ff4784be5277ad8a1bdd40 https://doi.org/10.1016/j.tet.2014.12.043 Zobrazit plný text záznamu Full Text from ScienceDirect