Dimethyl Sulfoxide → (R)-Tert-butyl 3-formyl-3,4-dihydroisoquinoline-2(1H)-carboxylate

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Reaction Conditions

Reaction Steps

To a solution of oxalyl dichloride (1.14 g, 9 mmol) in dichloromethane (30 mL) was added dimethyl sulfoxide (1.4 g, 18 mmol) at −78° C. After stirring at −78° C. for 20 min, to the mixture was added a solution of (R)-tert-butyl3-(hydroxymethyl)-3,4-dihydroisoquinoline-2(1H)-carboxylate (Step A (2), 1.32 g, 5 mmol) in dichloromethane (30 mL) and stirred at −78° C. for 30 to 45 min. Then triethylamine (36 mmol) was added and the reaction mixture was warmed up to rt over 2 h. Saturated sodium carbonate solution was added and extracted with dichloromethane. The solvent was removed and the crude mixture was purified by silica gel Flash chromatography to give the title compound: 1.2 g (90% yield). 1H NMR (CDCl3, 500 MHz) δ 1.48 (9H, d, J=35 Hz), 3.06-3.62 (2H, m), 4.45-4.81 (3H, m), 7.09-7.19 (4H, m), 9.48 (1H, d, J=25 Hz).

Provenance & Evidence