Hydrochloric Acid → trans-4-(1-Pentenylcyclohexyl)-3-fluorophenylboronic acid

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Reaction Steps

The compound (40) (15.8 g) and THF (100 ml) were put in a reaction vessel under a nitrogen atmosphere, and cooled to −74° C. sec-Butyllithium (1.00 M, in a n-hexane and cyclohexane solution; 20.0 ml) was added dropwise thereto in the temperature range of −74° C. to −70° C., and the mixture was stirred for another 2 hours. Subsequently, trimethoxyborane (7.3 g) in a THF solution (40 ml) was added dropwise thereto in the temperature range of −75° C. to −70° C., and the mixture was stirred for 8 hours while allowing the temperature to come to 25° C. The reaction mixture obtained was poured into an aqueous 1N—HCl solution (200 ml), and mixed. Then, toluene (200 ml) was added thereto and the mixture was allowed to be separated into organic and aqueous phases, and an extractive operation was carried out. The organic phase obtained was fractionated, washed with brine, and then dried over anhydrous magnesium sulfate. The solution obtained was washed with heptane and dried, giving 5.5 g of trans-4-(1-pentenylcyclohexyl)-3-fluorophenylboronic acid (41). The yield based on the compound (40) was 29.6%.

Provenance & Evidence