a Reaction conditions: cyclohexane (0.58 mmol, 50 mg, 1 equiv), NaCl, DIB, H2O, DCM. 18 W blue light, air, rt. b Yields are based on cyclohexane and detected by 1H NMR analysis using CH2Br2 as an internal standard.c Purple light instead of blue light.d In the dark. e DIB (0.155 mmol, 1 equiv), 4 (0.67 mL, 40 equiv), air, rt. Yields were based on DIB and detected by 1H NMR analysis using CH2Br2 as an internal standard.
halogenation and oxidation could proceed smoothly (11a-11c and12a-12c ). Unlike halogenation, the substrate structure had remarkable effects on the oxidation results. Saturated monocyclic hydrocarbon and linear alkanes were oxidized to the corresponding alcohol and ketone, without formation of overoxidized products. Hydroxyketone 12c was generated as the single product via α-oxidation of cyclic ketone, while substrates bearing one or more tertiary carbons were exclusively transformed into corresponding tertiary alcohols. It’s worth noting that a methyltied to aromatic ring (e.g., toluene) was directly overoxidized into carboxylic acid in high yield (85%), instead of alcohol or aldehyde.
Table 2 Activation of various C−H reagents with DIB