Tetrabutylammonium Fluoride → (3aR, 7R,7aR)-2-t-butoxycarbonyl-4,4-diphenyl-7-fluoroperhydroisoindole

Participants

Reaction Conditions

Reaction Steps

A solution of 4.87 g of (3aR, 7S, 7aR)-2-t-butoxycarbonyl-4,4-diphenyl-7trifluoromethylsulphonyloxyperhydroisoindole in 150 cm3 of dry difluoromethane is treated with 22.6 cm3 of a 1M solution of tetrabutylammonium fluoride in tetrahydrofuran and then stirred for 17 hours at 20° C and concentrated to dryness under reduced pressure (2.7 kPa). The residue is chromatographed on a silica gel column (particle size 0.2-0.063 mm, diameter 4.5 cm, height 35 cm), eluting under a nitrogen pressure of 0.4 bar with a cyclohexane and ethyl acetate mixture (75/25) and collecting fractions of 20 cm3. Fractions 28 to 38 are pooled and concentrated to dryness under reduced pressure (2.7 kPa) to give 1.44 g of (3aR, 7R,7aR)-2-t-butoxycarbonyl-4,4-diphenyl-7-fluoroperhydroisoindole in the form of white crystals; melting point 200° C., [α]D20 =-225° C. (c=1, CHCl3).

Provenance & Evidence