Dimethylformamide → (4R,9aR)-7-formyl-4,6-dimethyl-3,4,9,9a-tetrahydro-1H-2,4a,5-triaza-fluorene-2-carboxylic acid tert-butyl ester

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A solution of 0.41 g (1.07 mmol) (4R,9aR)-7-bromo-4,6-dimethyl-3,4,9,9a-tetrahydro-1H-2,4a,5-triaza-fluorene-2-carboxylic acid tert-butyl ester (example 6, intermediate) in 28 mL diethyl ether was cooled to −100° C. and treated with 0.80 mL (1.18 mmol) tert-butyl lithium (1.5M solution in n-pentane). After 15 min. 0.12 mL N,N-dimethylformamide was added and the temperature was raised to −78° C. After 45 min. the solution was poured into 10% aqueous ammonium chloride solution and extracted three times with ethyl acetate. The combined organic layers were washed with brine, dried over magnesium sulfate and filtered. The solvent was removed at a rotary evaporator and the residue was purified by column chromatography on silica gel (0.040–0.063 mm) with ethyl acetate:n-hexane (1:2) as eluant to give the compound as a yellow foam (80.2%).

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