Fig. 2: Scope of the primary, secondary, and tertiary C(sp³)–H hydroxylation of varied structural types of enones enabled by visible-light-induced hydrogen-atom transfer.

Reaction conditions: enone (0.20 mmol), Na₂-eosin Y (7 mol%), O₂ balloon, and MeCN (10 mL) at r.t. under the irradiation of 50 W 455 nm LEDs for 12 h; then thiourea (0.24 mmol, 1.2 equiv.) and MeOH (10 mL) were added and stirred for 4 h unless otherwise noted; Isolated yields are reported. ^aIrradiation time: 15 h; Acetone (10 mL) as solvent. ^bOn 0.18 mmol scale; Irradiation time: 5 h. ^cOn 0.08 mmol scale; 4 mol% Na₂-eosin Y. ^d8 mol% Na₂-eosin Y; irradiation time:15 h. ^eOn 2.04 mmol scale; MeCN (80 mL); MeOH (30 mL). ^fOn 0.12 mmol scale. ^gOn 0.085 mmol scale, 6 mol% Na₂-eosin Y, Irradiation time: 9 h. ^hOn 0.063 mmol scale; 5 mol% Na₂-eosin Y; Irradiation time: 8 h. ⁱ4 mol% Na₂-eosin Y. rt room temperature. rsm recovered starting material.