Dimethyl Sulfoxide → (2R,3S)-N-[(tert-Butyloxy)carbonyl]-3-amino-4-cyclohexyl-2-(triisopropylsilyloxy)butanal

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Reaction Steps

To a −78° C. solution of oxalyl chloride (10.8 mmol) in tetrahydrofuran (45 mL) was added dimethylsulfoxide (21.6 mmol). After stirring for 10 minutes, a solution of the title alcohol of Step 3 (10.8 mmol) in tetrahydrofuran (4.6 mL) was added dropwise. The solution was stirred for 20 minutes at −78° C. and then Et3N (45.1 mmol) was added. The reaction solution as allowed to warm to room temperature over a 2 hour period. The opaque, white mixture was poured into water (50 mL) and then extracted with ether (2×50 mL). The combined organic layer was washed with 1N HCl (50 mL), aqueous 5% NaHCO3 (50 mL), and brine (50 mL). The dried filtrate (MgSO4) was evaporated to give the title aldehyde (4.20 g, 100% yield). The 1H, 13C and APT NMR spectral data were consistent with the proposed structure.

Provenance & Evidence