Lithium Chloride → Tert-butyl 2-[3-(2,2-dimethylpropionylamino)-2-methoxycarbonylphenylethynyl]-pyrrolidine-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

A mixture of methyl 2-(2,2-dimethylpropionylamino)-6-trifluoromethanesulfonyloxybenzoate (Intermediate 39, 3.83 g), tert-butyl 2-tributylstannanylethynyl-pyrrolidine-1-carboxylate (Intermediate 41, 5.81 g), bis(triphenylphosphine)palladium(II) dichloride (0.702 g) and lithium chloride (1.28 g) in dimethylformamide (50 mL) was stirred and heated at 95° C. under nitrogen for 1 hour. After cooling, the mixture was concentrated in vacuo and the residue was partitioned between ethyl acetate and water. The organic layer was washed with water, dried (Na2SO4) and filtered. The filtrate was concentrated in vacuo and the residue was purified by chromatography on silica, eluting with a mixture of ethyl acetate and cyclohexane with a gradient of 0-25% to give tert-butyl 2-[3-(2,2-dimethylpropionylamino)-2-methoxycarbonyl-phenylethynyl]-pyrrolidine-1-carboxylate (3.71 g) as a viscous gum.

Provenance & Evidence