Potassium methoxide → HCID 73530210, compound

Participants

Reaction Conditions

Reaction Steps

20.5 g (0.1 mol) of 3-chloromethylcrotonaldehyde neopentyl glycol acetal were added to a solution of 31.0 g (0.1 mol) of 3-(5,5-dimethyl-1,3-dioxan-2-yl)-crotyl phenyl sulfone in 200 ml of DEK prepared as in Example 5A. The mixture was then cooled to 0° C. while stirring, and 17 g (0.24 mol) of solid potassium methylate were added over the course of 20 min. After 1 h the reaction mixture was allowed to warm to RT and was then stirred for 2 h. HPLC checks showed that 30.6 g (corresponding to 91% of theory) of 2,7-bis(5,5-dimethyl-1,3-dioxan-2-yl)-6-methyl-2,4,6-heptatriene had been produced. The reaction mixture was washed with a little water, and 60 ml of isopropanol and 60 ml of 2% strength H2SO4 and 17.4 g of propionaldehyde were added to the isolated DEK solution of the product for transacetalization. Hydrolysis was complete after stirring at 40° C. for 2 h. The aqueous phase was then separated off, and the organic phase was concentrated. After addition of 50 ml of isopropanol to the residue, 11.1 g (corresponding to 75% of theory) of 2,6-dimethyloctatrienedial crystallized, melting point 99°-100° C.

Provenance & Evidence