A solution of 30 mg of sodium borohydride in 2 cm3 of methanol is poured into a solution of 0.77 g of (−)-1-[(4-chlorophenyl)(4-formylphenyl)methyl]-3-[(3,5-difluorophenyl)(methylsulfonyl)methylene]azetidine in 20 cm3 of methanol at 0° C. under argon. After stirring for 4 hours at 0° C., water is added and the mixture is then extracted with dichloromethane. The organic phase is washed with a saturated aqueous sodium chloride solution, dried over magnesium sulfate and then evaporated to dryness under reduced pressure (2.7 kpa). The white foam obtained is purified on a silica gel column (particle size 0.04-0.06 mm, diameter 3.2 cm, height 17 cm) with, as eluent, a cyclohexane/ethyl acetate (60/40 by volume) mixture. 0.1 g of (+)-1-[(4-chlorophenyl)(4-hydroxymethylphenyl)methyl]-3-[(3,5-difluorophenyl)(methylsulfonyl)methylene]azetidine is obtained, after crystallization from 1.5 cm3 of absolute ethanol, in the form of white crystals melting at 190° C., [a]20D=+4.2° (c=0.5% in methanol) [NMR spectrum in DMSO-d6, T=300K, δ in ppm (300 MHz): 3.05 (3H, s, SCH3), 3.95 (2H, s, NCH2), 4.22 (2H, s, NCH2), 4.48 (2H, d, J=6 Hz, CH2O), 4.75 (1H, s, NCH), 5.15 (1H, t, J=6 Hz, OH), 7.20 (2H, m, 2CH arom.), 7.28 (2H, d, J=7 Hz, 2CH arom.), 7.40(5H, m, 5 CH arom.), 7.50 (2H, d, J=7 Hz, 2CH arom.)].
