Di-tert-butyl azodicarboxylate → di-tert-butyl 1-(1,1,3,3-tetramethyl-2,3-dihydro-1H-inden-5-yl)hydrazine-1,2-dicarboxylate

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Reaction Conditions

Reaction Steps

5-Bromo-1,1,3,3-tetramethyl-indan 19b (1.4 g, 5.53 mmol) was dissolved in 10 mL of tetrahydrofuran and cooled to −78° C. in a dry ice-acetone bath. t-Butyllithium (4.4 mL, 11.1 mmol) was added dropwise at the same temperature and the mixture was stirred for 40 minutes. A solution of di-tert-butyl azodicarboxylate (1.59 g, 6.92 mmol) in 10 mL of tetrahydrofuran was added dropwise by a constant-pressure addition funnel. The reaction mixture was stirred at −78° C. for 3 hours. The reaction was monitored by TLC until the disappearance of the starting materials. The reaction was quenched with 5 mL of methanol and was warmed up to room temperature. The mixture was extracted with ethyl acetate (20 mL×3). The combined organic extracts were dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by silica gel column chromatography to obtain the title compound di-tert-butyl 1-(1,1,3,3-tetramethyl-2,3-dihydro-1H-inden-5-yl)hydrazine-1,2-dicarboxylate 19c (1.326 g, yield 59.3%) as a yellow oil.

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