Trifluoroacetic acid → Tert-butyl 5-[2-(1(rs)-aminopropyl)-4(rs),5,5-trimethyl-1,3,2-dioxaborolan-4-yl]-3(rs)-methylvalerate

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Reaction Steps

0.82 g (2.27 mmol) of tert-butyl 5-[2-(1(RS)-chloropropyl)-4(RS),5,5-trimethyl-1,3,2-dioxaborolan-4-yl]-3(RS)-methylvalerate was dissolved in 10 ml of tetrahydrofuran and then cooledto -78° C. under a nitrogen atmosphere. 2.3 ml (2.3 mmol) of 1M lithium bis(trimethylsilyl)amide in tetrahydrofuran were added dropwise. The solution was then stirred overnight while slowly warming to 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. 0.52 ml (6.8 mmol) of trifluoroacetic acid was added and the solution was stirred at 0° C. for 30 minutes. The solution was evaporated and the residue was co-evaporated with toluene to give 1 g of tert-butyl 5-[2-(1(RS)-aminopropyl)-4(RS), 5,5-trimethyl-1,3,2-dioxaborolan-4-yl]-3(RS)-methylvalerate as an oil which was used in the next step without purification.

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