Trimethyl borate → 5-Ethyl-2-fluorophenol

Temperature

-60 °C

To a solution of 1-ethyl-4-fluorobenzene (5.0 g, 40.3 mmol) and PMDTA (8.5 mL, 40.7 mmol) in 20 mL THF at −40° C., was added BuLi (1.4 M in hexanes, 31.6 mL, 44.3 mmol). The tan suspension was stirred at −60° C. for 40 min, was recooled to −78° C., then B(OMe)3 (9.03 mL, 80.6 mmol). The mixture was stirred at −78° C. for 30 min, then was allowed to warm to rt. The reaction was quenched with 8 mL AcOH, then was cooled to 0° C. and treated with 9.8 mL 30% H2O2. The mixture was stirred for 30 min, then was quenched with aq. Na2SO3. The mixture was diluted with hexanes, washed with H2O (3×) and brine, dried (Na2SO4), filtered through 2″ silica gel (eluting with 20% EtOAc/hexanes), then concentrated to afford 5.42 g of Intermediate 188.1 as a pale yellow oil.

1. customwas recooled to −78° C.
2. stirringThe mixture was stirred at −78° C. for 30 min
3. temperatureto warm to rt
4. customThe reaction was quenched with 8 mL AcOH
5. temperaturewas cooled to 0° C.
6. additiontreated with 9.8 mL 30% H2O2
7. stirringThe mixture was stirred for 30 min
8. customwas quenched with aq. Na2SO3
9. additionThe mixture was diluted with hexanes
10. washwashed with H2O (3×) and brine
11. dry with materialdried (Na2SO4)
12. filtrationfiltered through 2″ silica gel (eluting with 20% EtOAc/hexanes)
13. concentrationconcentrated

ORD record

ord-c79307dd12ee4f2ba72a684b19c7e07d

Source dataset

uspto-grants-2009_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07576098B2