The light "on-off" stepwise one-pot method for 3,4-diaryl coumarins with potential AIE properties.

An efficient one-pot method involving visible-light-induced cyclization and Pd-catalyzed Suzuki cross-coupling processes to construct 3,4-diaryl coumarins is developed. Under the light on-off optimized conditions, a series of alkynoates and aryl boronic acids were well suitable for this catalytic system, and were successfully transformed into the corresponding products in moderate to high yields. Meanwhile, this synthetic system has good applicability for other Pd-catalyzed coupling reactions, such as Heck and Sonogashira reactions. 3,4,7-Triphenyl coumarin could be produced not only via the Suzuki reaction of 3-bromo-4,7-diphenyl with PhB(OH) 2 , but also via the Pd-catalyzed C–H activation. Based on the spectral studies, we found that some of the 3,4-diaryl coumarins may have AIE activities. This work provides a straight forward way to create valuable multi-substituted coumarins with potential AIE properties. Image 1 • The one-pot method involves photocatalysis and thermocatalytic processes. • The light "on-off" stepwise one-pot method has excellent substrate tolerance. • A straight forward way to obtain various types of multi-substituted coumarins. • Some of the synthesized 3,4-diaryl coumarins have potential AIE activities. [ABSTRACT FROM AUTHOR]