Butylamine → 2,4-Bis-benzyloxy-5-isopropenyl-benzoic acid benzyl ester

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Reaction Steps

A mixture of 2,4-bis-benzyloxy-5-bromo-benzoic acid benzyl ester (10.0 g, 20 mmol), potassium isopropenyl trifluoroborate (4.0 g, 27.2 mmol) and n-butylamine (6.0 mL, 60 mmol) in 2-propanol/water (2:1, 200 mL) was purged with N2 for 5 minutes. To this mixture was added [1,1′-bis(diphenyl-phosphino)ferrocene]dichloropalladium(II) (816 mg, 1.09 mmol) and the mixture was heated at reflux for 20 h. The mixture was allowed to cool to ambient then diluted with water (400 mL) and extracted with EtOAc (2×300 mL). The combined organic extracts were washed with 1M aqueous HCl, brine, dried (MgSO4), filtered through a plug of Celite and the filtrate reduced in vacuo to give the title compound (11.1 g) as a brown gum.

Provenance & Evidence