Alcohols, secondary, conversion into dehydrogenase

Several biochemical oxidations can be applied to the conversions of secondary alcohols into ketones. In a complex system containing horse liver alcohol dehydrogenase, ( )-trans-3-methylcyclohexanol and ( )-cis-2-methylcyclopentanol are dehydrogenated to (-)-(5)-3-methylcyclohex-anone (yield 50% ee 100%) and to (+ )-(5)-2-methylcyclopentanone (yield 55% ee 96%), respectively [1036]. 

Radioactive isotopes are commonly used for competitive KIE measurements in a double-label experiment, yielding kn/kj or ko/kj ratios on kcat/ M- This technique typically utilizes tracer-level radioactivity in the position of interest (primary or secondary) to monitor the transfer of radioactivity from reactant to product, and requires a remote label (e.g. C) in order to measure the conversion of unlabelled substrate to product. As an example, [ring- C(U)]benzyl alcohol and [l- H]benzyl alcohol (Scheme 10.2) can be used to simultaneously measure the primary and a-secondary kn/kj effects in the reaction catalyzed by alcohol dehydrogenase (ADH), as the tracer tritium is incorporated randomly into primary and a-secondary positions [6, 10]. 

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