Vinyl chloroformate → (3aRS,7aRS)-7,7-bis(3-fluorophenyl)-2-vinyloxycarbonylperhydro-4-isoindolone

Participants

Reaction Steps

A solution of (3aRS,7aRS)-2-benzyl-7,7-bis-(3-fluorophenyl)-4-perhydroisoindolone (92.2 g) in 1,2-dichloroethane (860 cc) is treated with vinyl chloroformate (26.3 cc) and the mixture is refluxed for 3 hours and then concentrated under reduced pressure (2.7 kPa). The residue is chromatographed (in two passes) on silica gel (particle size 0.04-0.063 mm, columns 8 cm in diameter and 35 cm high), eluting under a nitrogen pressure of 0.5 bar with a mixture of cyclohexane and ethyl acetate (75/25). The meringue obtained is crystallized from isopropyl ether to give (3aRS,7aRS)-7,7-bis-(3-fluorophenyl)-2-vinyloxycarbonyl-4-perhydroisoindolone (50.3 g). m.p.=152° C.

Provenance & Evidence