Trimethyl borate → 8,8-Dimethyl-8H-indolo[3,2,1-de]acridine-6-boronic acid

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Reaction Steps

93.7 g (259 mmol) of 6-bromo-8,8-dimethyl-8H-indolo[3,2,1-de]acridine (Br-1) are dissolved in 1500 ml of dry THF, 135 ml (337 mmol) of a 2.5 M solution of n-butyllithium in cyclohexane are added dropwise at −70° C., and, after 1 h, 37 ml of trimethyl borate (336 mmol) are added dropwise. The mixture is allowed to come to room temperature over the course of 1 h, the solvent is removed, and the residue, which is uniform according to 1H-NMR, is employed without further purification in the subsequent reaction. The yield is 77 g (235 mmol), corresponding to 91% of theory.

Provenance & Evidence