1- Acetoxy-2-methylcyclohexene

Hydrolysis of Enol Esters. Enzyme-mediated enantioface-differentiating hydrolysis of enol esters is an original method for generating optically active a-substituted ketones (84—86). If the protonation of a double bond occurs from one side with the simultaneous elimination of the acyl group (Fig. 3), then the optically active ketone should be produced. Indeed, the incubation of l-acetoxy-2-methylcyclohexene [1196-73-2] (68) with Pichia... 

A. l-Acetoxy-2-methylcyclohexene. Caution Since mixtures of perchloric acid with small amounts of organic material can explode violently, the perchloric acid should always he the last component added to the reaction mixture. 

Acetic acid 2-hydroxy-3-oxo-3-phenylpropyl ester 3 - Acetoxy-1 -cyclohexene 17)3-Acetoxy-estr-5(10)-ene-3-one rrara-Cyclohexenyl diacetate 4-Acetyl- 1-Methylcyclohexene 3-(Azidopropenyl)benzene... 

The nitration of enol acetates with acetyl nitrate is a regiospecific electrophilic addition to the 3-carbon of the enol acetate, followed by a hydrolytic conversion of the intermediate to the a-nitro ketone. With enol acetates of substituted cyclohexanones the stereochemistry is kinetically established. So, 1-acetoxy-4-methylcyclohexene (22) yields the thermodynamically less stable rrans-4-methyl-2-nitrocylo-hexanone (24) in greater proportion cis. trans = 40 60) (equation 8). This mixture can be equilibrated in favor of the thermodynamically more stable cis diastereomer (23) (cis. trans = 85 15). Nitration of 1-ace-toxy-3-methylcyclohexene (25) leads to frans-3-methyl-2-nitrocyclohexanone (26), which is also the thermodynamically more stable isomer (equation 9). No stereoselection occurs in the kinetically controlled nitration with acetyl nitrate of l-acetoxy-5-methylcyclohexene (27 equation 10), but the 1 1 mixture of the 5-methyl-2-nitrocyclohexanones can be equilibrated in favor of the trcms diastereomer (28) (cis trans = 10 90). 2-Alkyl-2-nitrocyclohexanones cannot be prepared in acceptable yields by nitration of the corresponding enol acetates with acetyl nitrate. 

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