Diisopropylamine → 3,5-Difluoro-4-(tributylstannyl)pyridine

Temperature

-78 °C

n-Butyl lithium (1.0 eq, 76 mmol, 47.6 mL, 1.6 M in hexanes) was added via dropping funnel to a solution of diisopropylamine (1.05 eq, 80 mmol, 11.2 mL) in THF (300 mL) at −78° C. under nitrogen (N2). The solution was stirred for 30 min at −78° C., then a solution of 3,5-difluoropyridine (1.05 eq, 80 mmol, 9.2 g) in THF (20 mL) was added dropwise via syringe. A beige precipitate was observed to form. The reaction stirred at −78° C. for 90 min then tributyltin chloride (1.0 eq, 76 mmol, 20.7 mL) was added dropwise via syringe and the resulting solution allowed to warm to RT over 2 h. Water (5 mL) was added, then roughly 250 mL of THF was removed on a rotary evaporator. The resulting material was diluted with diethyl ether (350 mL) and washed successively with water (2×200 mL), saturated sodium chloride solution (1×150 mL), dried over magnesium sulfate, filtered and concentrated in vacuo to afford the 3,5-Difluoro-4-tributylstannanyl-pyridine as a colourless oil (27.5 g, 88%). This material was used crude without further purification.

1. customat −78° C.
2. customto form
3. stirringThe reaction stirred at −78° C. for 90 min
4. temperatureto warm to RT over 2 h
5. customroughly 250 mL of THF was removed on a rotary evaporator
6. additionThe resulting material was diluted with diethyl ether (350 mL)
7. washwashed successively with water (2×200 mL), saturated sodium chloride solution (1×150 mL)
8. dry with materialdried over magnesium sulfate
9. filtrationfiltered
10. concentrationconcentrated in vacuo

ORD record

ord-89abf249a0f54f24b8c894f543473385

Source dataset

uspto-grants-2010_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07727985B2