Ethanol → 2-[1-hydroxy-meth-(Z)-ylidene]-4,4-dimethyl-cyclohexanone

Participants

Reaction Conditions

Reaction Steps

A dry round-bottomed flask was charged with sodium hydride (60% dispersion in mineral oil, 475 mg, 11.9 mmol) and diethyl ether (24 ml). The reaction was cooled to 0° C. and ethanol (0.06 ml, 1.03 mmol) was added dropwise. The suspension was stirred for at 0° C. for 20 min then a solution of 4,4-dimethylcyclohexanone (1.50 g, 11.9 mmol) and ethyl formate (1.45 ml, 17.8 mmol) in diethyl ether (3 ml) was added dropwise over 15 min. The yellow solution was stirred at 0° C. for 3 h then slowly allowed to warm to room temperature overnight. Ethanol (0.24 ml) was added and the mixture was stirred at room temperature for 1 h then quenched with water and extracted with diethyl ether. The aqueous layer was acidified with 6M HCl until pH=2 then extracted with diethyl ether (2×). The combined organic layers were washed with brine then dried over sodium sulfate, filtered and concentrated to give 1.30 g (71%) of 2-[1-hydroxy-meth-(Z)-ylidene]-4,4-dimethyl-cyclohexanone as a pale brown oil which was used without further purification. 1H NMR (CDCl3, 300 MHz): δ (ppm) 14.40 (br. s., 1H), 8.58 (s, 1H), 2.39 (t, J=6.8 Hz, 2H), 2.13 (s, 2H), 1.48 (t, J=6.8 Hz, 2H), 1.00 (s, 6H).

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