Fig. 2: Reaction scope for the photocatalytic sulfinylation of light alkanes with sulfur dioxide and trapping with electrophiles.

Photocatalytic reactions are performed in flow at 0.2 M concentration (SO₂, 0.6 mmol scale), with 5 equiv. of light alkane and 1 mol% of NaDT photocatalyst, under irradiation of UV-A light (365 nm, 144 W optical output power). Residence time of 1 h for isobutane, n-butane and propane, 2 h for ethane and methane. Pressure of 34 bar for isobutane, n-butane and propane, 52 bar for ethane and methane. The outflow is collected in a flask containing NaHCO₃ and alkyl bromide (0.2 mmol) and is stirred for 1 h at 60 °C. For reactions with methane, the photocatalytic step is performed at 4 mmol scale (SO₂), 6 mmol scale for entry 23 and 24. Diastereomeric ratio of the major isomer of compound 10 is 1:1. See Supplementary Information for further experimental details.