Methanol--water (1/1) → Ethyl 3-methyl-7-(4,5,6,7-tetrahydro-4,4,7,7-tetramethylbenzo[b]thien-2-yl)-2,4,6-octatrienoate

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Reaction Steps

4.50 g of [1-(4,5,6,7-tetrahydro-4,4,7,7-tetramethylbenzo[b]thien-2-yl)ethyl]triphenylphosphonium bromide and 1.3 g of ethyl 5-formyl-3-methylpenta-2,4-dienoate are dissolved in 70 ml of butylene oxide and the solution is heated at reflux for 2 hours. The cooled mixture is poured into a methanol/water mixture (6:4) and extracted several times with hexane. The hexane phase is washed three times with water, dried and evaporated. After filtration of the crude product over silica gel (eluting agent hexane/ether 9:1), there are obtained 2.4 g of ethyl 3-methyl-7-(4,5,6,7-tetrahydro-4,4,7,7-tetramethylbenzo[b]thien-2-yl)-2,4,6,-octatrienoate as a pale yellowish oil.

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