Trifluoroacetic acid → alpha-(RS)-allyl-4,4,5,5-tetramethyl-1,3,2-dioxaborolane-2-methylamine trifluoroacetate

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Reaction Steps

6.6 ml (6.6 mmol) of 1M lithium bis(trimethylsilyl)amide in tetrahydrofuran were added dropwise to a solution of 1.43 g (6.6 mmol) of 2-(1(RS)-chloro-3-butenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane in 20 ml of tetrahydrofuran under nitrogen at -78° C. The solution was then stirred overnight at room temperature. The solvent was removed by evaporation and the residue was taken up in diethyl ether. Insoluble material was removed by filtration and the filtrate was cooled to 0° C. 1.5 ml (19.8 mmol) of trifluoroacetic acid were added and thesolution was stirred at 0° C. for 30 minutes. The resulting precipitate was filtered off and dried to give 0.5 g of α-(RS)-allyl-4,4,5,5-tetramethyl-1,3,2-dioxaborolane-2-methylamine trifluoroacetate which was used in the next step without further purification.

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