(1S)-1-[(3aR,5S,6aR)-2,2-dimethyl-3a,5,6,6a-tetrahydrofuro[2,3-d][1,3]dioxol-5-yl]ethane-1,2-diol → (3aR,5S,6aR)-2,2-Dimethyltetrahydrofuro[2,3-d][1,3]dioxole-5-carbaldehyde

To a solution of (1S)-1-[(3aR,5S,6aR)-2,2-dimethyl-3a,5,6,6a-tetrahydrofuro[2,3-d][1,3]dioxol-5-yl]ethane-1,2-diol (compound 1c, 18 g, 90 mmol) in the MeOH (250 mL) cooled in ice bath was added sodium metaperiodate (23.1 g, 108 mmol). After being stirred at room temperature for 12 hours, the resulting suspension was filtered. The filtrate was concentrated in vacuo. The residue was purified by column chromatography on silica gel (eluting with 1:2 EtOAc in petroleum ether) to afford 14 g of (3aR,5S,6aR)-2,2-dimethyl-3a,5,6,6a-tetrahydrofuro[2,3-d][1,3]dioxole-5-carbaldehyde (compound 1d). MS obsd. (ESI+) [(M+NH4)+]: 190.