Borane → 4-Hydroxy-4-oxazol-2-yl-cyclohexanone

Temperature

-78 °C

To a solution of 1,3-oxazole (2.0 mL, 30.41 mmol) in THF (20 mL) was added 1.0 M solution of borane in THF (30.4 mL) at room temperature. The mixture was stirred for 1 hour before being cooled down to −78° C. To the above solution was added a 1.6 M solution of n-butyllithium in hexane (19 mL). After stirring at −78° C. for one hour, a solution of 1,4-dioxa-spiro[4.5]decan-8-one (5.22 g, 33.45 mmol) in THF (10 mL) was added. After being stirred at −78° C. for 5 hours, the reaction was quenched by addition of a 3 M solution of HCl in water (40 mL). The resulting solution was stirred at room temperature overnight, neutralized with potassium carbonate and extracted with EtOAc three times. The combined extracts were dried over MgSO4 and concentrated. Purification by flash chromatography on silica eluting with EtOAc afforded the desired product (3.9 g, 70%). LC-MS calculated for C9H11NO3: (M+H)+182; found 182.0.

1. stirringAfter stirring at −78° C. for one hour
2. stirringAfter being stirred at −78° C. for 5 hours
3. customthe reaction was quenched by addition of a 3 M solution of HCl in water (40 mL)
4. stirringThe resulting solution was stirred at room temperature overnight
5. extractionextracted with EtOAc three times
6. dry with materialThe combined extracts were dried over MgSO4
7. concentrationconcentrated
8. customPurification by flash chromatography on silica eluting with EtOAc

ORD record

ord-353c49ab2eb641499dacd3a84be82de9

Source dataset

uspto-grants-2007_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07307086B2