Methanesulfonyl chloride → Methyl {1-[bis(4-chlorophenyl)methyl]azetidin-3-ylidene}(3,5-difluorophenyl)acetate

Participants

Reaction Conditions

Reaction Steps

To a solution of 3.83 g (20.57 mmol) of methyl(3,5-difluorophenyl)acetate in 30 mL of THF was added a solution of 8.6 mL (21.51 mmol) of butyllithium (2.5M solution in hexanes) and stirred for 30 minutes at −78° C. A solution of 5.73 g (18.7 mmol) of 1-[bis(4-chlorophenyl)methyl]azetidin-3-one (7) in 10 mL THF was added and the solution was stirred for 2 h at −78° C. Then 2.28 g (18.6 mmol) of 4-dimethylaminopyridine, 3.3 mL (18.7 mmol) of N,N-diisopropylethylamine and 3.0 mL (37.4 mmol) of methanesulfonyl chloride was added and the solution was stirred for 1 h as it warmed from −78° C. to rt. The reaction mixture was then warmed to 45° C. and stirred for additional 2.5 h. The mixture was poured into 250 mL of ether and washed with 50 mL of aq NaHCO3. The organic layer was dried over Na2SO4 and concentrated. The residue was purified by silica gel chromatography with hexanes/ethyl acetate=15:1 to afford the title compound; 1NMR (CDCl3) δ 3.67 (s, 3H), 3.84 (m, 2H), 4.25 (m, 2H), 4.54 (s, 1H), 6.76 (m, 1H), 6.78 (m, 2H), 7.33 (m, 3H), 7.38 (m, 2H); Mass Spectrum: m/e=474 (M+1 35Cl, 35Cl) and 476 (M+1 35Cl, 37Cl).

Provenance & Evidence