4-[((1S)-2-(benzyloxy)-1-{[(triisopropylsilyl)oxy]methyl}ethyl)oxy]-4'-(trifluoromethoxy)-1,1'-biphenyl → (2S)-2-{[4'-(trifluoromethoxy)[1,1'-biphenyl]-4-yl)oxy}-3-[(triisopropylsilyl)oxy]-1-propanol

Participants

Reaction Steps

A mixture of the benzyl ether 80 (10.79 g, 0.019 mol) and 5% Pd—C (500 mg) in 1:1 EtOAc/EtOH (250 mL) was hydrogenated at 60 psi for 4 h. The catalyst was removed by filtration through Celite and the filtrate was concentrated under reduced pressure to give (2S)-2-{[4′-(trifluoromethoxy)[1,1′-biphenyl]-4-yl]oxy}-3-[(triisopropylsilyl)oxy]-1-propanol (81) as a viscous oil, sufficiently pure for use in the next step. Iodine (6.03 g, 0.024 mol) was added in portions at 20° C. to a vigorously stirred solution of the crude alcohol 81, triphenylphosphine (6.23 g, 0.024 mol) and imidazole (2.49 g, 0.036 mol) in benzene (100 mL) and stirring was continued for 1 h. After dilution with EtOAc the mixture was washed with water, 2N Na2SO3 and water again. The extract was evaporated and chromatographed on silica gel, eluting with EtOAc/petroleum ether (1:19), to give 4-[((1R)-2-iodo-1-{[(triisopropylsilyl)oxy]methyl}ethyl)oxy]-4′-(trifluoromethoxy)-1,1′-biphenyl (82) (9.08 g, 81% overall) as a colourless oil; 1H NMR (CDCl3) δ 7.54 (d, J=8.8 Hz, 2H), 7.48 (d, J=8.8 Hz, 2H), 7.26 (br d, J=8.8 Hz, 2H), 7.02 (d, J=8.8 Hz, 2H), 4.31-4.25 (m, 1H), 4.03 (dd, J=10.4, 4.8 Hz, 1H), 3.93 (dd, J=10.4, 5.6 Hz, 1H), 3.55 (dd, J=10.5, 5.6 Hz, 1H), 3.45 (dd, J=10.5, 4.8 Hz, 1H), 1.15-1.06 (m, 21H). APCI MS m/z 595 [M+H]+.

Provenance & Evidence