3,4-dihydro-2H-pyran → (4S)-4-(2-oxotetrahydro-2H-pyran-4-yloxy)pyrrolidin-2-one

Participants

Reaction Steps

To a solution of (S)-4-hydroxypyrrolidin-2-one (1.00 g, 9.89 mmol) in anhydrous dichloromethane (40 mL) was added 3,4-dihydro-2H-pyrane (1.35 mL, 14.84 mmol) and pyridinium p-toluenesulfonate (0.25 g, 0.99 mmol). The reaction mixture was stirred at ambient temperature for 18 hours, diluted with diethyl ether (100 mL) and washed with brine (25 mL). The organic layer was dried over anhydrous sodium sulfate, filtered and concentrated to afford (4S)-4-(2-oxotetrahydro-2H-pyran-4-yloxy)pyrrolidin-2-one as a clear oil (1.20 g, 61%): 1H NMR (300 MHz, CDCl3) δ 6.60 (br s, 1H), 4.98-4.57 (m, 1H), 4.57-4.46 (m, 1H), 3.89-3.70 (m, 1H), 3.68-3.22 (m, 3H), 2.69-2.22 (m, 2H), 1.89-1.50 (m, 6H).

Provenance & Evidence