DDQ-Mediated Oxidative Coupling: An Approach to 2,3-Dicyanofuran (Thiophene)

A facile oxidative coupling of α-carbonyl radicals to 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) for the synthesis of 2,3-dicyanofurans and thiophenes starting from readily available β-diketones, simple ketones, and β-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.