Sodium Carbonate → {4-[4-(tert-Butyl-dimethyl-silanyloxy)-cyclohex-1-enyl]-2-fluoro-phenyl}-carbamic acid benzyl ester

Participants

Reaction Conditions

Reaction Steps

4-Benzyloxycarbonylamino-3-fluoro-benzene boronic acid (2.53 g, 8.75 mmol, 1.25 equiv.) and LiCl (840 mg, 21 mmol, 3.0 equiv.) was placed in a 125 mL round bottom flask equipped with a condenser. To this was added aq. Na2CO3 (2 M, 14 mL) and EtOH (14 mL) to form a nice suspension. To this was transferred a solution of trifluoromethanesulfonic acid 4-(tert-butyl-dimethyl-silanyloxy)-cyclohex-1-enyl ester (2.52 g, 7 mmol, 1 equiv.) in toluene (36 mL). This suspension was subjected to a vacuum/nitrogen exchange three times. Pd(PPh3)4 (CAS 14221-01-3) (406 mg, 0.10 mmol, 7.5 mol %) was then added. The brown mixture was heated in an oil bath at 100° C. for 40 min when the suspension became dark. TLC showed the reaction was complete. The reaction was diluted with ether (20 mL) and water (20 mL). The two layers were separated, and the aqueous layer was extracted with Et2O (2×10 mL). The combined Et2O extracts were washed with sodium bicarbonate (5 mL), brine (5 mL) and dried (anhydrous potassium carbonate). The solution was passed through a short Celite/silica gel pad, eluted with EtOAc. The filtrate was concentrated in vacuo to obtain a crude product. This was purified on silica gel column to get a solid. The solid was crystallized in 10% EtOAc in heptane to get 2.45 g (77%) of the title compound as a white crystalline solid. mp 116.1-119° C.

Provenance & Evidence