Triethyl phosphite → (1S,5R,6S)-7-(diethoxy-phosphoryl)-5-methanesulfonyloxy-7-aza-bicyclo[4.1.0]hept-2-ene-3-carboxylic acid ethyl ester

Participants

Reaction Steps

To a solution of 383.4 mg of 14 and 4.0 mL toluene in a 10 mL round-bottom flask equipped with a magnetic stirrer, a reflux condenser maintained under an argon atmosphere at RT was added, 191 μl of triethyl phosphite. Nitrogen evolution began in about 5 min and after 30 min at RT the light yellow reaction mixture was heated to reflux for 5 h, then an additional 191 μl of triethyl phosphite were added and refluxing continued for another 2 h. The reaction mixture was cooled and evaporated at 40° C./60-10 mbar to yield 470 mg of the crude product as a yellow oil. The crude product was purified by SiO2 column chromatography using a 2/1 mixture of toluene and acetone. The combined fractions were evaporated and dried on a rotary evaporator 40° C./250-10 mbar to afford 87 mg of 16 as a yellow oil.

Provenance & Evidence