Water → (4R,9aR)-6-Ethyl-4-methyl-3,4,9,9a-tetrahydro-1H-2,4a,5-triaza-fluorene-2-carboxylic Acid Tert-butyl Ester

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Reaction Steps

To a solution of 0.70 g (1.90 mmol) (4R,9aR)-6-bromo-4-methyl-3,4,9,9a-tetrahydro-1H-2,4a,5-triaza-fluorene-2-carboxylic acid tert-butyl ester (Example 5, intermediate b) in 14 ml N,N-dimethylformamide was added 73.0 mg [1,1′-bis(diphenyphosphino)ferrocene]-dichloropalladium(II) and after 15 min, 4.8 ml of a 1M triethylborane solution in THF and 0.79 g (5.70 mmol) potassium carbonate were added. After 4 h another 2.4 ml triethylborane solution was added and the reaction mixture stirred overnight at 65 deg C. The mixture was cooled to room temperature and the suspension was poured into water and extracted twice with ethyl acetate. The combined organic phases were washed with brine, dried over magnesium sulfate, filtered and evaporated. The crude product was purified by column chromatography on silica gel (Q0.032–0.063 mm) with tert-butyl methyl ether:n-hexane (1:4) as eluant to yield the product as a colorless oil (89.5%).

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