2,2,6,6-Tetramethylpiperidine → 1-(4-chlorophenyl)-5-tributylstannyl-1H-pyrazole

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Reaction Conditions

Reaction Steps

2,2,6,6-Tetramethylpiperidine (TMP, 0.25 g, 1.78 mmol) was dissolved in dry THF (10 ml) in a flask with a magnetic stirrer bar. The flask was flushed with argon and kept under an inert atmosphere. The mixture was cooled to −78° C., and n-BuLi (1.1 ml, 1.6M, 1.78 mmol) was added dropwise during 1 minute. The mixture was stirred for 5 minutes at this temperature, before adding a solution of 1-(4-chloro-phenyl)-1H-pyrazole (0.21 g, 1.1 mmol) in dry THF (2 ml). The solution was added dropwise over 2 minutes, and the obtained solution was stirred at this temperature for 20 minutes, before adding Bu3SnCl (0.36 g, 1.1 mmol) over 1 minute. The solution was allowed to slowly warm to RT and was then quenched with MeOH (1 ml). The residual mixture was partitioned between EtOAc and water, and the organic phase was dried and concentrated. Purification on silica afforded 0.2 g (40%) of an oil.

Provenance & Evidence