1.51 g (3.0 mmol) of finely powdered (4-ethylenedioxybutyl)-triphenyl-phosphonium iodide are suspended in 10 ml of tetrahydrofuran and treated dropwise with a solution of 4.5 mmol of butyl-lithium in hexane. The solution turns red as the phosphonium iodide goes into solution as (4-ethylenedioxy-butylidene)-triphenyl-phosphorane. After approximately 10 minutes, 0.25 ml (4.5 mmol) of methyl iodide are added to this solution, which thereby becomes lighter, and the (4-ethylenedioxy-1-methylbutyl)-triphenyl-phosphonium iodide which is formed partially precipitates as an oil. After 10 minutes, 3.0 mmol of butyl-lithium in hexane are added dropwise and the solution thereby again becomes dark red.
