To Grignard reagent prepared from 33.7 g (173 mmol) of 2-(2-bromoethyl)-1,3-dioxane and magnesium in 300 ml of tetrahydrofuran (THF), a solution of 40.0 g (151 mmol) of 4-(4-pentylcyclohexyl) cyclohexane carbaldehyde (10) in 200 ml of THF was added dropwise, and the resultant solution was stirred for 3 hours. The reaction solution was added into 500 ml of 1N-hydrochloric acid, and the reaction product was extracted with 300 ml of toluene. The formed organic layer was sequentially washed with a saturated aqueous solution of hydrogen sodium carbonate and water, and dried over anhydrous magnesium sulfate. The solvent was distilled off under reduced pressure, and the residue was purified by silica gel column chromatography (eluent: hexane) to obtain 47.5 g (125 mmol) of 4-hydroxy-4-(4-(4-pentylcyclohexyl) cyclohexyl)butanal propylene acetal (11) at a yield of 82.8 percent.
