Trifluoromethanesulfonic anhydride → HCID 131715978, compound

Participants

Reaction Conditions

Reaction Steps

1.94 ml (13 mmol) of 1,5-diazabicyclo[5.4.0]undec-5-ene (DBU) and, after 20 minutes, 2.2 ml (13 mmol) of trifluoromethanesulphonic anhydride were added dropwise to a solution, which had been cooled to -78° C., of 3.68 g (10 mmol) of (2S,5R,6S)-2-allyloxycarbonyl-3,7-dioxo-6-[(1R)-1-tert.-butyldimethylsilyloxyethyl]-1-azabicyclo[3.2.0]heptane in 100 ml of anhydrous THF. The mixture was then stirred at -78° C. for 30 minutes and the solution was concentrated in vacuo to about 40 ml without the temperature rising above -20° C. Then, successively 20 ml of DMF, 2.1 ml (12 mmol) of ethyl diisopropylamine and 1.33 g (12 mmol) of 4-mercaptopyridine were added and the mixture was stirred at -20° C. for 1 h. The mixture was then diluted with ethyl acetate and poured into cold, saturated NaHCO3 solution. Extraction was carried out with ethyl acetate, followed by washing with saturated NaCl solution and drying with MgSO4. After evaporation of the solvent in vacuo and chromatography of the residue on 600 g of silica gel (toluene:ethyl acetate), 3.1 g (66%) of the title compound were obtained as a viscous oil, Rf: 0.30 (toluene:ethyl acetate 7:3).

Provenance & Evidence