1,8-Diazabicyclo(5.4.0)undec-7-ene → methyl 2-[(3R,4R)-3-allyl-5,5-dimethyl-1-oxo-2,8-diaza-6-oxaspiro[3,4]oct-7-en-2-yl]-3-methylbut-2-enoate

Participants

Reaction Steps

A solution of 1,8-diazabicyclo[5.4.0]undec-7-ene (17 μl) in methylene chloride (0.1 ml) was added to a solution of methyl 2-[(3R,4R)-3-(1-hydroxy-1-methylethyl)-3-isocyano-2-oxo-4-allylazetidin-1-yl]-3-methylbut-2-enoate (17 mg) in methylene chloride (1 ml) and acetone (1 ml) at 0° C., and the mixture was stirred for 20 hours at ambient temperature. Acetic acid (2 drops) was added to the reaction mixture at 0° C., and the mixture was evaporated in vacuo. The residue was dissolved in ethyl acetate (20 ml), and the solution was washed with 10% aqueous phosphoric acid, brine, phosphate buffer (pH 6.9), aqueous sodium bicarbonate and brine, dried over magnesium sulfate and evaporated in vacuo to give methyl 2-[(3R,4R)-3-allyl-5,5-dimethyl-1-oxo-2,8-diaza-6-oxaspiro[3,4]oct-7-en-2-yl]-3-methylbut-2-enoate (19 mg) as crude crystals.

Provenance & Evidence