Regioselective dioxygenation of ortho-trifluoromethylbenzoate by Pseudomonas aeruginosa 142: evidence for 1,2-dioxygenation as a mechanism in ortho-halobenzoate dehalogenation.

Pseudomonas aeruginosa strain 142 oxidizes 2-halobenzoates via a multicomponent oxygenase (V. Romanov and R.P. Hausinger, J. Bacteriol., 1994, 176(11), 3368-3374). The intermediacy of a highly unstable cis-diol in the reaction has been proposed. Direct evidence for this is currently lacking and the stereochemical course of the reaction cannot be inferred from previous studies. In this study, 2-trifluoromethylbenzoate was stoichiometrically oxidized by P. aeruginosa 142 to a chiral product identified as (-)2-trifluoromethyl-cis-1,2-dihydroxy-3,5-cyclohexadiene-1-carboxylic acid. These data rigorously establish a dioxygenative mechanism for 2-halobenzoate metabolism.