Tetrahydrofuran → ethyl p-[(E)-2-(2,3,4,5-tetrahydro-1-benzoxepin-8-yl)propenyl]benzoate

Participants

Reaction Steps

4.9 g of 2,3,4,5-tetrahydro-α-methyl-1-benzoxepine-8-methanol were dissolved in 50 ml of acetonitrile and treated with 13 g of triphenylphosphine hydrobromide. The reaction mixture was stirred at 40° C. for 24 hours. Thereafter, the majority of the solvent was removed under reduced pressure and the residue was partitioned between hexane and ethanol/water (8:2). The heavy phase was evaporated and dried, whereby 11.96 g of white phosphonium salt were obtained. 6.29 g of Phosphonium salt were dissolved in 13 ml of butylene oxide, treated with 2.6 g of ethyl 4-formylbenzoate and heated to reflux for 18 hours. Thereafter, the majority of the solvent was removed under reduced pressure and the residue was partitioned between hexane and ethanol/water (8:2). The light phase was dried over magnesium sulfate and evaporated. Chromatography on silica gel (petroleum ether/ethyl acetate (97:3)) and recrystallization from hexane yielded 1.4 g of ethyl p-[(E)-2-(2,3,4,5-tetrahydro-1-benzoxepin-8-yl)propenyl]benzoate, m.p. 71°-72° C.

Provenance & Evidence