2,6-Lutidine → (2S,3S,5S,6R,8S)-8-allyl-6-(3-chlorophenyl)-5-(4-chlorophenyl)-3-ethyl-2,8-dimethyl-2,3,5,6,7,8-hexahydrooxazolo[3,2-a]pyridin-4-ium triflate

Participants

Reaction Conditions

Reaction Steps

To a solution of (1R,2R,4S)-2-(3-chlorophenyl)-1-(4-chlorophenyl)-4-((4S,5S)-4-ethyl-5-methyl-4,5-dihydrooxazol-2-yl)-4-methylhept-6-en-1-ol (80 mg, 0.174 mmol) in CH2Cl2 (1737 μl) at −50° C. was added 2,6-lutidine (46.4 μl, 0.400 mmol) followed by trifluoromethanesulfonic anhydride solution, 1 M in methylene chloride (191 μl, 0.191 mmol). The reaction was stirred at −50° C. for 30 min and then treated with an additional 25 uL of trifluoromethanesulfonic anhydride solution, 1 M in methylene chloride, then 2 mL of sat. CuSO4. The reaction was warmed to rt and extracted with dichloromethane. The organic phase was dried over MgSO4, filtered and concentrated. Purification by column chromatography using 40 to 80% acetone in hexanes afforded (2S,3S,5S,6R,8S)-8-allyl-6-(3-chlorophenyl)-5-(4-chlorophenyl)-3-ethyl-2,8-dimethyl-2,3,5,6,7,8-hexahydrooxazolo[3,2-a]pyridin-4-ium triflate.

Provenance & Evidence