2,6-Lutidine → 1-[(2-Methoxy-5-methylphenyl)sulfonyl]indoline-4-carbaldehyde

Participants

Reaction Steps

OsO4 (9 mg, 0.05 mmol) was added to a stirred mixture of 1-[(2-methoxy-5-methylphenyl)sulfonyl]-4-vinylindoline (240 mg, 0.73 mmol; Intermediate 10) and 2,6-lutidine (170 μL, 1.46 mmol) in dioxane (12 mL). The mixture turned from colorless to black in 1 minute. Sodium periodate (0.625 g, 2.92 mmol) in water (4 mL, warmed to dissolve) was added. A grey precipitation was immediately formed. The mixture was stirred for 25 min, combined with an earlier batch of this intermediate (followed this experimental and starting from Intermediate 10; 60 mg, 18 mmol), and partitioned between 2M aqueous HCl (25 mL) and DCM (25 mL). The organic layer was dried, filtered and concentrated to give the title compound (360 mg, still some dioxane according to HNMR) as a black sticky oil. MS (ESI+) for C17H17NO4S m/z 332 (M+H)+.

Provenance & Evidence