Bromide Controlled Hydrazo Coupling of Phenols and Anilines via Organic Photocatalysis

Abstract

Phenols and anilines are the most common and critical structural entities subsists in natural products, agro-materials, and bioactive compounds.1 The para- selective cross aminative coupling in phenols or anilines is a significant demand as their para- amino derivatives occur in many essential drug molecules, dyes and natural products. Here an efficient organic photocatalytic para- selective amination and aminative dearomatization of phenols and anilines with azodicarboxylates is developed. The formation of para- amino phenol or aniline and para- amino cyclohexadinone depends whether it has a para- substitution or not. The use of organic photocatalyst riboflavin tetraacetate (RFTA) is successfully demonstrated to avoid metal contamination. The reaction condition is simple and mild giving high selectivity with good to excellent yield. A broad substrate scope and nice functional group tolerance, with scalability and post functionalization makes the protocol worthy one.