Water → 4-[4-Nitro-2-(3,3,5,5-tetramethylcyclohex-1-enyl)phenyl]piperazine-1-carboxylic acid t-butyl ester

Participants

Reaction Steps

To a solution of 4-(2-chloro-4-nitrophenyl)piperazine-1-carboxylic acid t-butyl ester (5.93 g, 17.3 mmol) produced in Example (88a) in 1,2-dimethoxyethane (70 mL) were added 4,4,5,5-tetramethyl-2-(3,3,5,5-tetramethylcyclohex-1-enyl)[1,3,2]dioxaborolane (5.5 g, 20.8 mmol) produced in Example (4b), tripotassium phosphate (5.51 g, 26 mmol) and water (3 mL). Tetrakis(triphenylphosphine)palladium(0) (1.0 g, 0.865 mmol) was added to the mixture while stirring at room temperature under a nitrogen atmosphere. The mixture was then stirred for 3 hours at an external temperature of 80° C., and then for 7 hours at an external temperature of 100° C. Tetrakis(triphenylphosphine)palladium(0) (830 mg, 0.718 mmol) was added to the reaction mixture, and stirring was continued for 22 hours and 30 minutes. Ethyl acetate was added to the reaction mixture, which was then filtered through Celite. The filtrate was concentrated and the resultant residue was extracted with ethyl acetate, and the obtained organic layer was washed with water and brine. The organic layer was dried over anhydrous magnesium sulfate and then the desiccant was filtered off and the filtrate was concentrated under reduced pressure. The resultant residue was purified by silica gel column chromatography (ethyl acetate/heptane) to give 1.08 g of the title compound as an orange oil.

Provenance & Evidence