Tridecyltriphenyl phosphonium bromide (0.3 mole) was dissolved in 900 ml of tetrahydrofuran and cooled to 0° C. in an ice-salt bath while stirring under argon. A 2.2N solution of n-butyllithium in hexane (0.36 mole) was added dropwise over a period of 30 minutes. The mixture was stirred for an additional 20 minutes and then cooled to -70° C. in a dry ice-acetone bath. The 4-hydroxybut-2(E)-ene-1-al tetrahydropyranyl ether (0.3 mole) in 225 ml of tetrahydrofuran was added dropwise over a period of 35 minutes and the mixture stirred for an additional hour at -70° C. The mixture was then poured into 6.25 liters of ether and stirred for 20 minutes. The resulting mixture was filtered through glass fiber filter paper. The filtrate was evaporated and the residue triturated with hexane, filtered and evaporated to give a ~3:1 mixture of trans:cis isomers of the desired compound.
