Photocatalyzed chemodivergent aerobic oxidation of naturally occurring Viridicatin and derivatives

A chemodivergent reaction is an appealing way to construct molecules with enriched structure diversity in a controlled manner. A plethora of methodologies were developed based on this concept, and transition metal-catalysis plays a central role among others catalysis systems own to its longstanding history. While a chemodivergent reaction based on organo-catalysis, especially photocatalysis, is rather limited as these concepts were only prevalent in the last two decades. With the ever-increasing importance of photocatalysis, a chemodivergent reaction based on such an activation pathway would be a meaningful direction. Herein, an efficient chemodivergent strategy for visible light photocatalysis is developed. By employing commercially available Rose Bengal as a photocatalyst, naturally occurring Viridicatin and its derivatives can be transformed into three different types of products through switchable single electron transfer (SET) or energy transfer (EnT) processes. Mechanistic studies have revealed that the oxygen as a reactive center, rather than carbon, is favored, which accounts for the first example of a C–O homo-dimerization product.