Dimethyl Sulfoxide → Ethyl 5-(1-acetyl-1H-indol-3-yl)pent-2-enoate

Participants

Reaction Steps

To a stirring solution of oxalyl chloride (11.4 mL, 0.13 mol) in CH2Cl2 (440 mL) at -78° C. was added dry DMSO (12.4 mL, 0.17 mol) dropwise. After 5 minutes, gas evolution ceased and the alcohol 4 (19 g, 87 mmol) in CH2Cl2 (40 mL) was added. After 30 minutes, NEt3 (73 mL, 0.52 mol) was added to effect a thick slurry. The cooling bath was removed and the reaction stirred for an additional 15 minutes before adding (carbethoxymethylene)triphenyl phosphorane (33.5 g, 96 mmol). After 2.0 hours, the reaction mixture was diluted with ether and then washed with H2O (2 times), 5% KHSO4 and brine, dried (MgSO4), and concentrated. Flash chromatography (20% ethyl acetate/hexanes) gave the olefin 5 (14 g) as a white solid.

Provenance & Evidence