Ultrasound-assisted synthesis of benzophenones by Stille cross-coupling reactions. Optimization via experimental design

A series of diaryl ketones have been synthesized in moderate to excellent yields through the selective cross-coupling reaction of benzoyl chlorides with arylstannanes using a sonochemical variation of the Stille coupling. Ultrasound significantly enhances this useful organometallic transformation affording the desired products in higher yields and shorter reaction times than conventional reactions. The scope of the protocol has been explored with a selection of arylstannanes and different aroyl chlorides as reaction partners. Remarkably, no by-products resulting from homo-coupling could be detected. The ultrasound-promoted cross-coupling reaction was optimized through experimental design.

Graphical abstractA series of diaryl ketones have been synthesized in moderate to excellent yields through the selective cross-coupling reaction of benzoyl chlorides with arylstannanes using a sonochemical variation of the Stille coupling. Remarkably, no by-products resulting from homo-coupling could be detected. The ultrasound-promoted cross-coupling reaction was optimized through experimental design.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► The increment of the rate of the reaction, reducing energy consumption. ► The absence of sub-products, simplifying the isolation of the products. ► Catalytic turnovers of 4800 have been achieved. ► The method could be applied to the synthesis of triaryl diketones in a single step. ► Ultrasound-promoted cross-coupling reaction was optimized by experimental design.