Tetrahydropyranes diacetoxy

To a solution of2 (340 mg, 0.9 mmol) in THF (30 mL) cooled to —78°C K-Selectride (1.34 mL of a 1 -M solution in THF) was slowly added (1 h) under nitrogen atmosphere. The reaction mixture was stirred for an additional 1 h, quenched with an aqueous saturated solution of NaHC03 (20 mL) and allowed to attain room temperature. The product was extracted with ethyl acetate (4 x 20 mL), the combined extracts were dried (MgS04) and concentrated to dryness. The residue was dissolved in dichloromethane (30 mL), then triethylamine (500 p,L, 3.6 mmol), acetic anhydride (250 p.L, 2.6 mmol), and a crystal of AJA-dimethylaminopyridine (DMAP) were added, and the mixture was left under nitrogen at room temperature. After 24 h the solution was concentrated to dryness and the residue was chromatographed on a silica gel column with hexane-ethyl acetate (3 1) to give 25,35,4/ ,6/ -3,4-diacetoxy-2-(l-menthyloxy)-6-(2-furyl)-tetrahydropyran 4 (290 mg, 79%) mp 127°-129°C, [a]D - 5.3° (c 0.8, CHC13). 

Tetrahydropyran 4.5-Diacetoxy-2-isothiocyanat-3-iodo-6-methyl-E21e, 5303 (En + KSCN/ I2)... 

Tetrahydropyran 6-(Acetoxy-methyl)-4,5-diacetoxy-3-iodo-2-isothiocyanat- E21e, 5303 (En + I2/KSCN)... 

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