138769-92-3

Advanced intermediates for the syntheses of tetrodotoxin reported by the groups of Fukuyama, Alonso, and Sato were prepared. Key steps include the toluene dioxygenase mediated dihydroxylation of either iodobenzene or benzyl acetate. The resulting diene diols were transformed into Fukuyama's intermediate in six steps, into Alonso's intermediate in nine steps, and into Sato's intermediate in ten steps.

The whole-cell fermentation of aromatic coumpounds with Escherichia coli JM109 (pDTG601) on a medium scale (10-15L) produces enantiopure cyclohexadienediols. A detailed procedure for the fermentation is described, and yields for several metabolites are provided. A similar procedure using E. coli JM109 (pDTG602) affords catechols. The dienediols are useful for asymmetric synthesis, and several important targets originating from these metabolites are tabulated.

Toluene dioxygenase-catalysed oxidation of mono-substituted benzene substrates (R = F, Cl, Br, I, Me, Et, CH2OAc, CH=CH2, C=CH, CF3, CN, OMe, OEt, SMe) in growing cultures of Pseudomonas putida UV4 yielded the corresponding cis-dihydrodiol metabolites. Palladium-catalysed cross-coupling of cis-(1S,2S)-1,2-dihydroxy-3-iodocyclohexa-3,5-diene with a range of tributyltin compounds provided a chemoenzymatic route to a further series of cis-dihydrodiol derivatives of monosubstituted benzenes (R = D, CH2CH=CH2, Bun, SEt, SPr1, SBu1, SPh, SC6H4Me-4). The enantiopurities and absolute configurations of the cis-dihydrodiols, obtained by both enzymatic and chemoenzymatic routes, were determined by several new methods including 1H NMR spectroscopic analysis of the bis-MTPA esters of the 4-phenyl-1,2,4-triazoline-3,5-dione cycloadducts, X-ray crystallography, circular dichroism spectroscopy and stereochemical correlation.

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Metabolism of bromobenzene and iodobenzene by growing cultures of Pseudomonas putida UV4 gave the corresponding cis-dihydrodiol products 1 and 2 in high yields; subsequent direct chemical substitution of the halogen atoms in these metabolites provided a new range of enantiomerically pure cis-dihydrodiols of known absolute configuration.