Acetyl-2-methylcyclohexanone

A solution of 2-methyl-l-(trimethylsilyloxy)cyclohex-l-ene (10 mmol) in dichloromethane (8 ml) was added dropwise over 15 min with stirring to acetyl chloride (10 mmol) and TiCl4 (10 mmol) in dichloromethane (15 ml) at —78 °C. After 1 h at —78 °C, the reaction mixture was allowed to warm to ambient temperature over 2 h. It was then diluted with ether (20 ml), and poured into saturated sodium hydrogen carbonate solution (50 ml). Normal work-up, followed by chromatography on silica gel, gave the /3-diketone (9.1 mmol, 91%). 

With silyl ketene acetals, anhydrous zinc bromide (1 mol%) is the preferred catalyst. 

Conjugate addition to nitro-oleflns—1,4-diketone synthesis 

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Acetic Anhydride, Carbon Tetrachloride, and 2-Methylcyclohexanone. During acetylation of the enolized ketone, the 70% perchloric acid must be added last.6... 

Acetyl-n-valeric acid has been prepared by the oxidation of 1-methylcyclohexene with potassium permanganate 5 by the oxidation of 2-methylcyclohexanone with chromic oxide and sulfuric acid 6 by the reaction of methylzinc iodide on the ethyl ester of adipic acid chloride and saponification of the ethyl ester of 5-acetyl-w-valeric acid so obtained 7 by the saponification of the ethyl ester of diacetylvaleric acid 2 and through the hydrolysis of ethyl a-acetyl-6-cyanovalerate with boiling 20% hydrochloric acid.3... 

Chiral -substituted ketones.2 Conjugate addition of (CH3)3A1 to the ketal (2) of cyclohexenone derived from (S,S)-1 followed by acetylation results in the adduct 3, which is hydrolyzed by acid to (S)-3-methylcyclohexanone (4) in 77% ee. The ketal derived from (2R,3R)-2,3-butanediol undergoes a similar conjugate addition with low asymmetric... 

The a,j8-unsaturated ketonic structure of the parent is even clearer in the next two examples. 2-Isopropylidenecyclohexanone (43), when heated at 80°C with guanidine, gave an excellent yield of 2-imino-4,4-dimethyl-3,4,5,6,7,8-hexahydroquinazoline (44). With ammonium thiocyanate in boiling toluene and with urea at 40°C in a current of hydrogen chloride gas, good yields of the corresponding 2-thione and 2-one, respectively, were obtained. Similarly, 2-acetyl-l-methylcyclohexanone and ammonium thiocyanate provided a moderate yield of 4,8a-dimethyl-3,4,5,6,7,8,8a-hexa-hydroquinazoline-2-thione (45).31... 

Reduced phenanthridines have been prepared from anilines and derivatives of cyclohexanone. In the first reported example, Borsche obtained 6,9-dimethyl-7,8,9,I0-tetrahydrophenanthridine (130a) in 15% overall yield by condensing 6-acetyl-3-methylcyclohexanone with aniline and cyclizing the resultant anil (129a) with sulfuric acid. Although the anil (129b) of 2-acetylcyclohexane-l,3-dione cyclizes in... 

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