DDQ-Mediated Oxidative Coupling: An Approach to 2,3-Dicyanofuran (Thiophene)
摘要:
A facile oxidative coupling of alpha-carbonyl radicals to 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) for the synthesis of 2,3-dicyanofurans and thiophenes starting from readily available beta-diketones, simple ketones, and beta-keto thioamides in up to 95% yield in one step was developed. Mechanistic investigations revealed that a radical process could be involved in this transformation, and a water promoted C-C bond cleavage pathway is proposed for the formation of 2,3-dicyanofurans and thiophenes.