tert-Butyl 4-oxopiperidine-1-carboxylate → tert-Butyl 4-(7-fluorobenzofuran-2-yl)-4-hydroxypiperidine-1-carboxylate

Temperature

-78 °C

To a solution of 7-fluorobenzofuran (0.3 g, 1.807 mmol) in dry THF (4.8 mL) at −78° C. under an argon atmosphere was slowly added BuLi (1.3 mL, 2.078 mmol). Upon completion of addition, the mixture was stirred at −78° C. for 20 min. After this time, a solution of tert-butyl 4-oxopiperidine-1-carboxylate (0.36 g, 1.807 mmol) in THF (2.4 mL) was slowly added. The reaction mixture was warmed to −40° C., where it stirred for 2 hrs. At the conclusion of this period, the reaction mixture was quenched with aqueous NH4Cl (saturated, 5 mL) and then extracted with EtOAc (3×5 mL). The combined organic layers were washed with H2O (2×4 mL), brine (5 mL), dried (Na2SO4), filtered, and concentrated to yield a residue. The residue was purified by column chromatography (silica gel, hexanes/EtOAc gradient 0 to 60% EtOAc) to afford Compound 1D as a white solid (530 mg, 94.7% purity, 83% yield).

1. customat −78° C.
2. additionUpon completion of addition
3. temperatureThe reaction mixture was warmed to −40° C.
4. stirringwhere it stirred for 2 hrs
5. customAt the conclusion of this period, the reaction mixture was quenched with aqueous NH4Cl (saturated, 5 mL)
6. extractionextracted with EtOAc (3×5 mL)
7. washThe combined organic layers were washed with H2O (2×4 mL), brine (5 mL)
8. dry with materialdried (Na2SO4)
9. filtrationfiltered
10. concentrationconcentrated
11. customto yield a residue
12. customThe residue was purified by column chromatography (silica gel, hexanes/EtOAc gradient 0 to 60% EtOAc)

ORD record

ord-88ae03ec17fb46f1922edfcfd70bff8c

Source dataset

uspto-grants-2014_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08729084B2