Sodium Sulfite → 2,3,4,5-tetrahydro-1-benzothiepine 1,1-dioxide

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Reaction Conditions

Reaction Steps

To a stirred solution of 13.44 g (31.07 mmol) of enantiomerically-enriched tetrahydrobenzothiepine-1-oxide (obtained from Step 7) in 150 mL of methylene chloride was added 9.46 g of 68% m-chloroperoxybenzoic acid (37.28 mmol, Sigma) at 0° C. After stirring at 0° C. for 2 hours, the mixture was allowed to warm up to room temperature and stirred for 4 hours. 50 mL of saturated Na2SO3 was added into the mixture and stirred for 30 minutes. The solution was then neutralized with 50 mL of saturated NaHCO3 solution. The methylene chloride layer was separated, dried over MgSO4, and concentrated in vacuo to give 13.00 g (97.5%) of the enantiomerically-enriched tetrahydrobenzothiepine-1,1-dioxide (4R,5R) as a light yellow solid: 1H NMR (CDCl3) δ 0.89-0.95 (m, 6H), 1.09-1.42 (m, 12H), 2.16-2.26 (m, 1H), 3.14 (q, J=15.6 Hz, 1H), 3.87 (s, 3H), 4.18 (s, 1H), 5.48 (s, 1H), 6.54 (dd, J 10.2 Hz, 2.4 Hz, 1H), 6.96-7.07 (m, 3H), 7.40 (d, J 8.1 Hz, 2H), 8.11 (dd, J=8.6 Hz, 5.9 Hz, 1H).

Provenance & Evidence