反应详情

温度

-70 °C

1-Bromo-4-(cyclopropylmethyl)benzene (2.11 g) was dissolved in anhydrous tetrahydrofuran (20 ml) and cooled to −70° C. under an argon atmosphere. A 1.25M solution of n-butyl lithium in hexane (8.8 ml) was added at such a rate that the temperature did not exceed −65° C. with stirring, which was maintained for a further 30 minutes. Trimethyl borate was added slowly keeping the temperature below −60° C. and the reaction mixture was stirred for a further 1.5 hours at −70° C. After warming to −5° C., the reaction was quenched by the addition of a saturated aqueous solution of ammonium chloride (50 ml) and the organic phase was separated. The aqueous layer was extacted with ethyl acetate (2×30 ml) and combined organic phases were dried (MgSO4) and evaporated to give 4-(cyclopropylmethyl)phenylboronic acid (1.52 g); 1H NMR (d6-DMSO): 0.2 (d, 2H), 0.5 (d, 2H), 0.9-1.07 (m, 1H), 2.5 (partly obscured by DMSO), 7.2 (d, 2H), 7.7 (d, 2H); mass spectrum (−ve ESP) 175 (M−H)−.

1. customdid not exceed −65° C.
2. temperaturewhich was maintained for a further 30 minutes
3. customthe temperature below −60° C.
4. stirringthe reaction mixture was stirred for a further 1.5 hours at −70° C
5. temperatureAfter warming to −5° C.
6. customthe reaction was quenched by the addition of a saturated aqueous solution of ammonium chloride (50 ml)
7. customthe organic phase was separated
8. dry with materialwere dried (MgSO4)
9. customevaporated