Hydrochloric Acid → 1,2,3,4-Tetrahydro-1,4-methanonaphthalene-5-boronic Acid

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Reaction Conditions

Reaction Steps

100 ml (250 mmol) of n-butyllithium (2.5M in hexane) are added dropwise to a solution, cooled to −78° C., of 44.6 g (200 mmol) of 5-bromo-1,2,3,4-tetrahydro-1,4-methanonaphthalene in 500 ml of THF. The reaction mixture is stirred at −78° C. for 1 h, and a mixture of 33.5 ml (300 mmol) of trimethyl borate in 50 ml of THF is then added rapidly. After warming to −10° C., the mixture is hydrolysed using 10 ml of 2.5M hydrochloric acid, and 500 ml of methyl tert-butyl ether are then added. The organic phase is separated off, washed with water, dried over sodium sulfate and evaporated to dryness. The residue is taken up in 200 ml of n-heptane, and the colourless solid is filtered off with suction, washed with n-heptane and dried under reduced pressure. Yield: 24.1 g (128 mmol), 64.1% of theory; purity: 98% according to 1H-NMR.

Provenance & Evidence