Potassium Carbonate → (R)-2-Ethyl-piperazine-1,4-dicarboxylic acid 4-tert-butyl ester 1-(2,6-difluoro-3-methyl-benzyl) ester

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Reaction Steps

A mixture of (R)-2-ethyl-piperazine-1,4-dicarboxylic acid 4-tert-butyl ester 1-(3-bromo-2,6-difluoro-benzyl) ester (226 mg), tetrakis(triphenylphosphine)palladium (56 mg), trimethylboroxine (122 mg) and potassium carbonate (200 mg) in dioxane (5 mL) was heated to reflux with stirring for 6 h. The cooled was mixture was partitioned between water and ethylacetate. The water phase was extracted once with ethylacetate, organic phases were pooled and dried with Na2SO4 to yield after evaporation a dark oil (259 mg). This residue was purified by column chromatography (silica gel; n-hexane/ethylacetate gradient) to yield 160 mg (82%) of a yellow oil. MS (ISP): 416.4 (M+H)+.

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