7,7-Dioxo-5,6-dihydrothieno[2,3-b]thiopyran-4-one → (R)-(+)-5,6-Dihydro-4H-thieno[2,3-b]-thiopyran-4-ol-7,7-dioxide

Participants

Reaction Conditions

Reaction Steps

To a magnetically stirred solution of 5,6-Dihydro-4H-thieno[2,3-b]-thiopyran-4-one-7,7-dioxide (12) (1.00 g, 4.94 mmol) in dry THF (14 mL) was added (S)-diphenylprolinol-borane complex from Example 12 (132 mg, 0.494 mmol). The solution was cooled to -15° C. and a solution of borane-dimethyl sulfide (10M, 0.4 mL, 4.0 mmol) in dry THF (6.8 mL) was added at a rate to maintain the internal temperature at -151° C. The solution was stirred at -15° C. for 1 hour then at 22° C. for 6 hours. The product was isolated by the method decribed in Example 34 Step E. The enantiomeric ratio of the purified product was 95:5.

Provenance & Evidence