4-Nitrobenzenesulfonyl chloride → (R)-N-(2-(6-bromo-3-fluoro-4-(triethylsilyl)pyridin-2-yl)-2-hydroxypropyl)-4-nitrobenzenesulfonamide

Participants

Reaction Conditions

Reaction Steps

To a solution of crude (R)-1-amino-2-(6-bromo-3-fluoro-4-triethylsilanyl-pyridin-2-yl)-propan-2-ol hydrochloride (43.5 g, 109 mmol) in 335 ml THF was added a solution of NaHCO3 (21.02 g, 250 mmol) in 500 ml water. The mixture was cooled to 0-5° C. and a solution of 4-nitrobenzenesulfonyl chloride (26.5 g, 120 mmol) in 100 ml THF was added in a dropwise. The resulting emulsion was stirred overnight while allowing the temperature to reach rt. The mixture was extracted with TBME. The organic layer was dried with MgSO4.H2O, filtered and evaporated to give an orange resin which was purified on a silica gel column by eluting with Hexanes/10-20% EtOAc to yield 37.56 g of the title compound as a yellow resin. TLC (Hex/EtOAc 3/1) Rf=0.34; HPLC: RtH11=1.678 min; ESIMS: 548, 550 [(M+H)+, 1Br]; 1H-NMR (400 MHz, DMSO-d6): 8.40 (d, 2H), 8.06 (t, 1H), 7.97 (d, 2H), 7.45 (d, 1H), 5.42 (s, 1H), 3.23 (d, 2H), 1.44 (s, 3H) 0.97-0.81 (m, 15H); Chiral HPLC (Chiralpak AD-H 1213, UV 210 nm): 90% ee.

Provenance & Evidence