Trifluoroacetic acid → HCID 13551501, compound

To 258 mg (1.2 mmol) of (E)-1-methoxy-3-tert-butyldimethylsilyloxy-1,3-butadiene and 130 mg (1 mmol) of n-butylglyoxylate was added at 0° C. the solution of the complex in toluene obtained above. After stirring for 2 hours, 0.1 ml of trifluoroacetic acid was added thereto. Next, the reaction mixture was stirred for 5 minutes, then poured into a saturated aqueous solution of sodium bicarbonate and filtered through celite. Then the filtrate was extracted with ether thrice and dried over anhydrous magnesium sulfate. After distilling off the solvent under reduced pressure, the residue was purified by silica gel column chromatography (hexane/ethyl acetate=10/1). Thus 79 mg of n-butyl 3,4-dihydro-4-oxo-2H-pyran-2-carboxylate was obtained (yield: 40%). When measured with CHIRALPAK AD column (manufactured by Daicel Chemical Industries) [hexane:i-PrOH=10:1, flow rate: 1.0 ml/min], the optical purity of this product was 50% e.e.

1. customobtained above
2. stirringNext, the reaction mixture was stirred for 5 minutes
3. filtrationfiltered through celite
4. extractionThen the filtrate was extracted with ether thrice
5. dry with materialdried over anhydrous magnesium sulfate
6. distillationAfter distilling off the solvent under reduced pressure
7. customthe residue was purified by silica gel column chromatography (hexane/ethyl acetate=10/1)

ORD record

ord-e1c261335a5645248a31c93905c08504

Source dataset

uspto-grants-2000_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06025503