Dimethyl Sulfoxide → HCID 73553419, compound

Participants

Reaction Steps

TFAA (0.459 mL, 3.25 mmol, 3.2 equiv) in DCM (0.5 mL) was added dropwise to DMSO (0.303 mL, 4.26 mmol, 4.2 equiv) in DCM (0.5 mL) at −78° C. After 30 minutes, (S)-2-(3-chloropyrazin-2-ylamino)-1-((3aS,4S,6aR)-2,2-dimethyl-6-(trityloxymethyl)-4,6a-dihydro-3aH-cyclopenta[d][1,3]dioxol-4-yl)ethanol (1-6) (593 mg, 1.01 mmol, 1 equiv) in DCM (2.7 mL) was added dropwise. The resulting mixture was stirred at −78° C. for 1 hour, at which point Hunig's base (1.06 mL, 6.09 mmol, 6 equiv) was added. After 30 minutes, the reaction was partitioned between sodium bicarbonate and DCM, and the aqueous phase was extracted with DCM (3×20 mL), the combined organic extracts were washed with water, dried (MgSO4), and concentrated. The resulting yellow residue was purified via flash chromatography on silica gel column (ethyl acetate/hexanes) to yield 2-(3-chloropyrazin-2-ylamino)-1-((3aS,4R,6aR)-2,2-dimethyl-6-(trityloxymethyl)-4,6a-dihydro-3aH-cyclopenta[d][1,3]dioxol-4-yl)ethanone (1-7) as a colorless oil. 1H NMR (500 MHz, CDCl3) δ 7.93 (d, 1H, J=3 Hz), 7.64 (d, 1H, J=3 Hz), 7.21-7.49 (m, 15H), 5.94 (s, 1H), 5.62 (m, 1H), 4.97 (t, 1H, J=6 Hz), 4.60-4.77 (2 d, 1H, J=7 Hz), 3.95 (d, 1H, J=14 Hz), 3.75 (m, 2H), 3.31 (m, 1H), 1.36 (s, 3H), 1.33 (s, 3H).

Provenance & Evidence