Dimethyl Sulfoxide → HCID 86615473, compound

Participants

Reaction Conditions

Reaction Steps

A solution of dry DMSO (1.75 g, 22.4 mmol) in dry CH2Cl2 (20 mL) was added to a solution of (COCl)2 (1.52 g, 12 mmol) in dry CH2Cl2 (40 mL), which had been cooled to −78° C. under a nitrogen atmosphere. The resulting reaction mixture was further stirred at the same temperature for another 15 min before a solution of alcohol 107 (1.27 g, 8 mmol) in dry CH2Cl2 (15 mL) was added carefully over 10 min, while the temperature was kept at −78° C. The stirring was continued for 30 min and then dry Et3N (8.0 g, 80 mmol) was added at the same temperature. The mixture was allowed to warm to room temperature, CH2Cl2 (100 mL) was subsequently added, and again it was cooled to −78° C. The solution was treated with saturated NaCl (40 mL) and then the reaction mixture was allowed to warm to room temperature. The organic layer was separated, dried (Na2SO4), and concentrated under reduced pressure. The crude aldehyde 36d (3.0 g) was dissolved in CH2Cl2 (40 mL) and treated with SnCl2 (5.10 g, 24 mmol) and ethyl diazoacetate (1.14 g, 10 mmol). The mixture was stirred at room temperature for 3 h. The reaction mixture was filtered through a pad of Celite (20.0 g), and the resulting organic layer was concentrated. The desired keto ester was purified by column chromatography (silica gel; hexanes:EtOAc-hexanes, 95:5) to furnish 110 as oil (0.69 g, 36%) with identical spectroscopic properties as those reported under Method A.

Provenance & Evidence