1-Naphthaldehyde → 6-Bromo-1-naphthalen-1-ylmethyl-1,3-dihydro-indol-2-one

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Reaction Steps

2-(2-Amino-4-bromo-phenyl)-malonic acid di-tert-butyl ester (7.73 g, 20.0 mmol) and 1-napthylaldehyde (3.0 ml, 22.0 mmol) were dissolved in 80 ml of acetic acid (AcOH) under an atmosphere of dry N2. To this solution was added 95% sodium triacetoxyborohydride (NaHB(OAc)3) (5.8 g, 26 mmol) and the solution was stirred for 45 minutes. The reaction mixture was concentrated under vacuum and then stirred in 100 ml of a 1:1 solution of DCM/water. To this mixture was slowly added NaHCO3 until the pH˜8. The DCM layer was then washed with saturated aqueous NaHCO3 and dried over MgSO4, filtered and concentrated under vacuum to give a foam which was subsequently dissolved in a solution of 80 ml of TFA and 10 ml of triethylsilane under an atmosphere of dry N2. The mixture was stirred overnight after which time the precipitate was collected, washed with hexanes and dried under vacuum to give 6.43 g of the titled compound as a white solid in 90% yield.

Provenance & Evidence