Triphenylsilanol → (2,6,6-Trimethyl-4-oxocyclohex-2-en-1-ylidene)acetaldehyde

Beteiligte Stoffe

Reaktionsschritte

Triphenylsilanol (22 g) and 80 g (0.45 mol) of 3,5,5-trimethyl-4-hydroxy-4-ethynylcyclohex-2-en-1-one and 1.6 g of stearic acid are dissolved in 800 ml of xylene, treated with 1.92 ml of vanadium isopropylate and heated to reflux temperature while stirring. After 31/2 hours the reaction mixture is cooled and washed with 5% sodium bicarbonate, whereby an emulsion results. The organic phase is then separated, the emulsion is also separated and extracted with ether. The organic phases are dried over magnesium sulphate and concentrated. The residue (117.9 g) is distilled (oil bath 130°-170°; 0.001 mm Hg). In this manner there are obtained 51.8 g (64.8%) of (2,6,6-trimethyl-4-oxo-2-cyclohexen-1-ylidene)acetaldehyde (Z:E=about 3:1).

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