Dimethyl Sulfoxide → 1-((4S,5S)-2,2-dimethyl-5-vinyl-1,3-dioxolan-4-yl)-2-(trityloxy)ethanone

Participants

Reaction Steps

To a stirred solution of (COCl)2 (28.69 ml, 57.38 mmol, 2 M solution in CH2Cl2) in CH2Cl2 (200 ml) was dropwise added a solution of DMSO (8.9 ml, 125.51 mmol) in CH2Cl2 (30 ml) at −78° C., and the reaction mixture was stirred at the same temperature for 30 minutes. A solution of alcohol 3 (15.44 g, 35.86 mmol) in CH2Cl2 (30 ml) was added and the reaction mixture was stirred at −78° C. for 1 hour. Triethylamine (32.99 ml, 236.68 mmol) was added at −78° C. and then the reaction mixture was allowed to warm to room temperature and stirred for 1 hour. A saturated ammonium chloride solution was added carefully at 0° C. and the reaction mixture partitioned between CH2Cl2 and water. The organic layer was dried, filtered, and evaporated under reduced pressure. The residue was purified by silica gel column chromatography using hexane and ethyl acetate (6:1) to give ketone 4 (13.83 g, 90%) as a white solid; 1H NMR (400 MHz, CDCl3) δ 7.46-7.23 (m, 15H), 5.56 (ddd, J=17.2, 10.4, 6.8 Hz, 1H), 5.26 (td, J=16.8, 1.2 Hz, 1H), 5.13 (td, J=10.4, 1.2 Hz, 1H), 4.88-4.84 (m, 1H), 4.76 (d, J=7.6 Hz, 1H), 4.06 (d, J=18.0 Hz, 1H), 3.72 (d, J=18.4 Hz, 1H), 1.41 (s, 3H), 1.34 (s, 3H).

Provenance & Evidence