Sulfonation and Trifluoromethylation of Enol Acetates with Sulfonyl Chlorides Using Visible‐Light Photoredox Catalysis

Abstract

A mild, practical method to prepare α‐sulfonyl and α‐trifluoromethyl ketones from readily available enol acetates and sulfonyl chlorides has been developed using visible‐light photoredox catalysis. The method could be used with a wide range of enol acetates and sulfonyl chlorides, and gave the desired products in satisfactory to excellent yields.

Synthesis of β‐Keto Sulfones via Coupling of Aryl/Alkyl Halides, Sulfur Dioxide and Silyl Enolates through Metal‐Free Photoinduced C–X Bond Dissociation

“…2‐([1,1′‐Biphenyl]‐4‐ylsulfonyl)‐1‐phenylethan‐1‐one (3f) : White solid; yield: 56.5 mg (85%); 1 H NMR (400 MHz, CDCl 3 ): δ =7.95 (d, J= 8.2 Hz, 4 H), 7.73 (d, J= 8.3 Hz, 2 H), 7.60 (m, 3 H), 7.52–7.41 (m, 5 H), 4.78 (s, 2 H): 13 C NMR (100 MHz, CDCl 3 ): δ =188.1, 147.1, 139.0, 137.2, 135.7, 134.4, 129.3, 129.1, 129.1, 128.9, 128.7, 127.8, 127.4, 63.5.…”

“…1‐Phenyl‐2‐(pyridin‐3‐ylsulfonyl)ethan‐1‐one (3j) : White solid; yield: 29.1 mg (56%); 1 H NMR (400 MHz, CDCl 3 ): δ =9.12 (s, 1 H), 8.89 (d, J= 3.9 Hz, 1 H), 8.22 (d, J= 8.0 Hz, 1 H), 7.94 (d, J= 7.5 Hz, 2 H), 7.65 (t, J= 7.4 Hz, 1 H), 7.51 (t, J= 7.8 Hz, 3 H), 4.82 (s, 2 H); 13 C NMR (100 MHz, CDCl 3 ): δ =187.8, 154.6, 149.5, 136.7, 135.4, 135.3, 134.7, 129.1, 129.0, 123.6, 63.3.…”

Photocatalytic fluoroalkylation reactions of organic compounds

“…A variety of reagents, such as CF 3 I, 50,[55][56][57]59,62,66,67 silver trifluoroacetate, triflyl chloride (CF 3 SO 2 Cl), 49,64 the Langlois reagent, the Togni reagent, 51,53,54,60,65 the Umemoto reagent, 48,52,58,63,65 and the Shibata reagent, 61 can act as trifluoromethyl radical (•CF 3 The excited catalyst can reduce the R f X source (oxidative quenching pathway), regeneration of the catalyst follows by means of an electron donor or else, the photoexcited catalyst could be reduced by an electron donor to a one-electron reduced species that transfers an extra electron to the R f X source (reductive quenching pathway).…”

“…: [Ru(bpy) 3 ] 2+ and facIr(ppy) 3 (bpy = 2,2´-bipyridine and ppy = 2-phenylpyridinate), can induce both oxidative 48,49,51,54,58,60,[63][64][65] and reductive 50,[55][56][57]59,62 quenching cycles, owed to the positive driving forces for electron transfer to typical perfluoroalkyl halides. 7 The competition of the two pathways precludes the elucidation of the molecular parameters of the catalysis.…”

Recent advances in sulfur- and phosphorous-centered radical reactions for the formation of S–C and P–C bonds

“…A Zhang and Yu groups reported the utility of visible-light-absorbing transition metal photocatalysts such as Ir(ppy) 3 to promote the sulfonyl radical addition to vinyl acetates for the synthesis of α-sulfonyl ketones 180 (Scheme 79) 142. The Lei group reported a new method for aerobic hydroxysulfonylation of alkenes.…”