Potassium Phosphate, Tribasic → 1,1-dimethylethyl 5-(2-cyano-3-fluorophenyl)-2,3-dihydro-1H-indole-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

A mixture of 2-fluoro-6-iodobenzonitrile (2.65 g, 10.73 mmol), 1,1-dimethylethyl 5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-2,3-dihydro-1H-indole-1-carboxylate (3.78 g, 10.95 mmol, 1.02 equiv), tricyclohexylphosphine (301 mg, 1.07 mmol, 0.1 equiv), Pd2(dba)3 (491 mg, 0.54 mmol, 0.05 equiv) and K3PO4 (3.87 g, 18.24 mmol, 1.7 equiv) in 40 mL of dioxane and 10 mL of water in a 150 mL pressure vessel was bubbled under argon for 10 min. The mixture was capped and heated in an oil bath at 100° C. for 18 h. LCMS showed conversion complete. The mixture was filtered through Celite. The filtrate was concentrated in vacuo. The residue was partitioned between EtOAc (130 mL) and brine (40 mL). The organic was dried over Na2SO4, filtered, and concentrated in vacuo. The dark brownish oil was stored in the refrigerator for 20 h, which became a cake. Trituration in DCM/hexane (1:4), breaking up of the cake, filtration, and drying under vacuum at room temperature gave 1,1-dimethylethyl 5-(2-cyano-3-fluorophenyl)-2,3-dihydro-1H-indole-1-carboxylate (2.63 g) as a greyish solid. The filtrate was concentrated in vacuo and absorbed onto a dryload cartridge. Purification was done on an RS-120 g silica gel cartridge using gradient elution of 1% EtOAc in hexane to 40% EtOAc in hexane. The product eluted from 29-34% EtOAc in hexane. Concentration in vacuo and drying under vacuum additional 1,1-dimethylethyl 5-(2-cyano-3-fluorophenyl)-2,3-dihydro-1H-indole-1-carboxylate (0.77 g) as a yellow foam.

Provenance & Evidence