Boron trifluoride etherate → 2-Benzhydryl-2H-pyran-4(3H)-one

Temperature

-78 °C

A solution of boron trifluoride diethyl etherate (7.8 g, 55 mmol) in dry ether (50 ml) was added to a stirred mixture of E-1-methoxy-3-trimethylsilyloxybuta-1,3-diene (8.3 g, 48 mmol), diphenylacetaldehyde 1 (11.4 g, 58 mmol) and dry ether (300 ml) cooled to −78° C. After one hour, the mixture was allowed to reach 0° C. for three hours. The deep red reaction mixture was quenched with saturated aqueous NaHCO3, and the mixture was allowed to come to room temperature. The organic phase was separated and the aqueous phase was extracted with ether (3×70 ml). The combined organic phases were washed with brine, and dried over anhydrous Na2SO4. Evaporation of solvent under reduced pressure and purification of the crude product by chromatography (hexane/ethyl acetate 8:2) gave 2-diphenylmethyl-2,3-dihydro-4H-pyran-4-one 2 (10.2 g, 80.2%, yield) as a yellow solid.

1. waitto reach 0° C. for three hours
2. customThe deep red reaction mixture
3. customwas quenched with saturated aqueous NaHCO3
4. customto come to room temperature
5. customThe organic phase was separated
6. extractionthe aqueous phase was extracted with ether (3×70 ml)
7. washThe combined organic phases were washed with brine
8. dry with materialdried over anhydrous Na2SO4
9. customEvaporation of solvent
10. customunder reduced pressure and purification of the crude product by chromatography (hexane/ethyl acetate 8:2)

ORD record

ord-3e4d7ca359824f05a4e21d0f3df086a7

Source dataset

uspto-grants-2011_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07915433B2