This project was financially supported by the 333 High-Level Talent Project of Jiangsu Province, the Changzhou Sci & Tech Program (CJ20220021), the Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology (BM2012110), the Advanced Catalysis and Green Manufacturing Collaborative Innovation Center of Changzhou University, and the Research Fund of the Changzhou Vocational Institute of Engineering (11120101120002, 11130300120001, and 11130900120004).
A photocatalytic synthesis of aryl allyl sulfones by a radical cascade reaction from an aryl diazonium salt, DABCO·(SO2)2 and 3-bromoprop-1-ene has been developed. This reaction employed DABCO·(SO2)2 as the SO2 source and a polyaniline–graphitic carbon nitride–titanium dioxide composite as the photocatalyst. A series of substrates were tolerated, providing the corresponding products in good yields. Moreover, the photocatalyst could be readily recovered and reused several times with only a slight decrease in its catalytic activity.
131-(Allylsulfonyl)-4-nitrobenzene (2a): Typical ProcedureA 25 mL flask equipped with a stirrer bar was charged with 4-nitrobenzenediazonium tetrafluoroborate (1a; 0.75 mmol, 1.5 equiv), DABCO (1 mmol, 2 equiv), 3-bromoprop-1-ene (0.5 mmol, 1 equiv), and PANI(40%)–g-C3N4–TiO2 (20 mg) in MeCN (5 mL). The mixture was then irradiated with a 30 W CFL (10 cm distance) and stirred at rt under N2 for 10 h. When the reaction was complete, the catalyst was collected by filtration and the mixture was extracted with EtOAc. The organic layer was dried (Na2SO4) and concentrated in vacuum, and the residue was purified by flash column chromatography (silica gel PE–EtOAc) to give a yellow solid; yield: 91.9 mg (81%).1H NMR (400 MHz, CDCl3): δ = 8.40 (d, J = 8.9 Hz, 2 H), 8.07 (d, J = 8.9 Hz, 2 H), 5.80 (ddt, J = 17.5, 10.1, 7.4 Hz, 1 H), 5.37 (dd, J = 10.2, 0.7 Hz, 1 H), 5.15 (dd, J = 17.1, 1.0 Hz, 1 H), 3.87 (d, J = 7.4 Hz, 2 H). 13C NMR (100 MHz, CDCl3) δ = 150.9, 143.7, 130.1, 125.6, 124.2, 123.9, 60.7. MS (ESI): m/z = 228.2 [M + H]+.
