2-Isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane → (2-(Cyclopropylmethoxy)-5-fluorophenyl)boronic acid

Temperatur

-40 °C

To a solution of Example 274a (0.1 g, 0.408 mmol) in tetrahydrofuran (2 mL) at −20° C. was added nBuLi (0.180 mL of a 2.5 M solution in hexanes, 0.449 mmol). The reaction mixture was stirred for 2 hours, then cooled to −40° C. 2-Isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (0.092 mL, 0.449 mmol) was added dropwise. The reaction mixture was stirred for 30 minutes. The reaction mixture was quenched with 1M citric acid at 0° C. The mixture was stirred at ambient temperature for 1 hour and then extracted with ethyl acetate. The layers were separated, and the organic layer was dried over anhydrous sodium sulfate, filtered, and concentrated. The crude material was purified by flash chromatography (silica gel, 10-33% ethyl acetate/hexanes gradient) to provide the title compound (23 mg, 20% yield).

1. stirringThe reaction mixture was stirred for 30 minutes
2. customThe reaction mixture was quenched with 1M citric acid at 0° C
3. stirringThe mixture was stirred at ambient temperature for 1 hour
4. extractionextracted with ethyl acetate
5. customThe layers were separated
6. dry with materialthe organic layer was dried over anhydrous sodium sulfate
7. filtrationfiltered
8. concentrationconcentrated
9. customThe crude material was purified by flash chromatography (silica gel, 10-33% ethyl acetate/hexanes gradient)

ORD-Eintrag

ord-fd52f32bc4814cd59a02cac416f2167a

Quelldatensatz

uspto-grants-2016_03

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US09296741B2