Hydroquinone → 4a,5,8,8a-Tetrahydro-2,8-dimethoxy-6-trimethylsilyloxynapthalene-1,4-dione

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

In a 50 mL round bottom flask, 2-methoxy-1,4-benzoquinone (2.3 g, 16.7 mmol) was suspended in toluene (30 mL). Hydroquinone (95 mg) was added and the resulting suspension was stirred magnetically for 5 min. 1-Methoxy-3-trimethylsilyloxy-1,3-butadiene (Aldrich, used as received, 5.0 g, 4.5 mL, 29.1 mmol) was added in one portion and the reaction was heated under N2 at 60° C. using an oil bath for 18 h. The reaction was removed from the oil bath, allowed to cool to rt and the solvent was removed by evaporation. Crystallization occurred after cooling the mixture to -30° C. for 1 hour. The colorless solid was collected by filtration and washed with hexane (30 mL) giving 4a,5,8,8a-tetrahydro-2,8-dimethoxy-6-trimethylsilyloxynapthalene-1,4-dione ##STR137## as a colorless powder (3.6 g, 11.6 mmol, 70%, >95% pure by 1H NMR, mp 108°-110° C.; 1H NMR (CDCl3) δ0.52 (s, 9H), 2.2-2.4 (m, 2H), 3.18 (s, 3H), 3.47 (t, 1H), 3.80 (s, 3H), 3.92 (m, 2H), 5.20 (d, 1H), 6.12 (s, 1H).

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