2,2,6,6-Tetramethylpiperidine → 3-Chloro-2,6-difluoro-4-methoxyphenylboronic Acid

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Reaction Conditions

Reaction Steps

5.1 g of 2,2,6,6-tetramethylpiperidine were dissolved using 200 ml of anhydrous THF. 12.4 ml of a 2.7M solution of n-butyllithium in heptane were added at −10° C. and the mixture was stirred for 10 minutes at −10° C. The mixture was then cooled to −70° C. and a solution of 5.0 g 2-chloro-3,5-difluoroanisole in 40 ml of anhydrous THF added dropwise at −70° C. Stirring was continued for 1 h at −75° C. Then, 7.9 g of triisopropyl borat were added and the mixture was allowed to warm to room temperature. Stirring was continued for 1 h at room temperature. Then, the reaction mixture was poured into 200 ml of a saturated aqueous NaHSO4-solution and extracted twice using 100 ml EA each. The organic layer was washed using 100 ml of a saturated aqueous NaHSO4-solution, dried using MgSO4 and evaporated to yield 5.6 g of the title compound that was used without further purification.

Provenance & Evidence