benzyl 4-methoxy-3-oxobutanoate

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of benzyl 4-methoxyacetoacetate (84 g, 0.37 mol), 3,4-difluorobenzaldehyde (52.5 g, 0.0.37 mmol), and piperidinium acetate (1.58 g, 2.63 mmol) in benzene (1L) were added molecular sieves (400 g) and the mixture was stirred at room temperature for 48 h. The molecular sieves were removed by filtration and the solvent was evaporated from the filtrate under reduced pressure. The residue was purified by column chromatography on silica gel using chloroform/ethyl acetate (100:3) to get the product as a white powder (118 g, 91%). The NMR showed this product to be a mixture of cis and trans isomers. The molecular sieves were removed by filtration the solvent was evaporated from the filtrate under reduced pressure The residue was purified by column chromatography on silica gel