A Comparative Study of the Synthesis of 3‐Substituted Catechols using an Enzymatic and a Chemoenzymatic Method

A series of cis‐dihydrodiol metabolites, available from the bacterial dioxygenase‐catalysed oxidation of monosubstituted benzene substrates using Pseudomonas putida UV4 , have been converted to the corresponding catechols using both a heterogeneous catalyst (Pd/C) and a naphthalene cis‐diol dehydrogenase enzyme present in whole cells of the recombinant strain Escherichia coli DH5α(pUC129: nar B). A comparative study of the merits of both routes to 3‐substituted catechols has been carried out and the two methods have been found to be complementary. A similarity in mechanism for catechol formation under both enzymatic and chemoenzymatic conditions, involving regioselective oxidation of the hydroxyl group at C‐1, has been found using deuterium labelled toluene cis‐dihydrodiols. The potential, of combining a biocatalytic step (dioxygenase‐catalysed cis‐dihydroxylation) with a chemocatalytic step (Pd/C‐catalysed dehydrogenation), into a one‐pot route to catechols, from the parent substituted benzene substrates, has been realised.