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Dibenz[a,j]anthracene 3,4-oxide (2) and the isomeric oxepine (19) were synthesised simultaneously from a common dibromoester precursor (9). The oxepine isomer (19) was also formed by photoisomerisation of the arene oxide (2). Resolution and absolute configuration assignment of each enantiomer of trans-3-bromo-4-hydroxy-1,2,3,4-tetrahydrodibenz[a,j]anthracene (10) was achieved by chromatographic separation and recrystallisation of the MTPA diastereoisomers (11a/11b). The (+)-(3S, 4S)bromo-MTPA ester (11a) was used in a seven-step synthesis of the chiral metabolite (–)-(3R, 4R)-trans-3,4-dihydroxy-3,4-dihydrodibenz[a,j]anthracene (3). The (–)-(3R, 4R)-bromo-MTPA ester diastereoisomer (11b) similarly served as a precursor of (3S, 4R)-dibenz[a,j] anthracene 3,4-oxide (2) which spontaneously racemised via an unstable oxepine isomer (18).

Dibenz[a,j]anthracene 3,4-oxide (2) and the isomeric oxepine (19) were synthesised simultaneously from a common dibromoester precursor (9). The oxepine isomer (19) was also formed by photoisomerisation of the arene oxide (2). Resolution and absolute configuration assignment of each enantiomer of trans-3-bromo-4-hydroxy-1,2,3,4-tetrahydrodibenz[a,j]anthracene (10) was achieved by chromatographic separation and recrystallisation of the MTPA diastereoisomers (11a/11b). The (+)-(3S, 4S)bromo-MTPA ester (11a) was used in a seven-step synthesis of the chiral metabolite (–)-(3R, 4R)-trans-3,4-dihydroxy-3,4-dihydrodibenz[a,j]anthracene (3). The (–)-(3R, 4R)-bromo-MTPA ester diastereoisomer (11b) similarly served as a precursor of (3S, 4R)-dibenz[a,j] anthracene 3,4-oxide (2) which spontaneously racemised via an unstable oxepine isomer (18).

Benz[a]anthracene 3,4-oxide 2, when synthesised from optically pure dibromo ester precursors, was found to have racemized spontaneously and was accompanied by anthra[2,1-b]oxepine 14. Photoisomerization of benz[a]anthracene 3,4-oxide 2, triphenylene 1,2-oxide 4 and benz[a]anthracene 1,2-oxide 5 proceeds via an oxygen-walk mechanism to yield anthra[2,1-b]oxepine 14, phenanthro[10,9-b]oxepine 16 and anthra[2,1-f]oxepine 17 respectively.

Bacterial metabolism of the dihydronaphthalenes 1 or 3 using cultures of Pseudomonas putida UV4 yielded the arene hydrates of naphthalene 2 or a mixture of 4 and 5 respectively; these arene hydrates have also been obtained in homochiral form either by synthesis from enantiomerically pure alcohols 10 and 12 and arene oxide 11 precursors or by chiral stationary phase HPLC separation of arene hydrate enantiomers.

The synthesis of triphenylene 1,2-oxide (1,2-epoxy-l,2-dihydrotriphenylene)(2) from both racemic and optically pure precursors is reported. Racemic triphenylene 1,2-oxide (2) was obtained in each case, in accord with PMO calculations which predict rapid racemization. Liver microsomal metabolism of both triphenylene (1) and racemic triphenylene 1,2-oxide (2) yielded predominantly the (–)-enantiomer (92 and 85%, respectively) of the trans-dihydro diol (5). The 1R5,2R configuration for (–)-(5) has been established by preparative h.p.l.c. separation of the dimenthyloxyacetate diastereoisomers of the dihydro diol (5) and stereochemical correlation to (–)-(1R,2R)-trans-2-bromo-1-menthyloxyacetoxy-1,2,3,4-tetrahydrotriphenylene (9A) whose absolute configuration has been assigned by X-ray crystallographic analysis.

Diarene oxides have been synthesised by a single step oxidation of monoarene oxides using dimethyldioxirane, and by a three step cyclization sequence from the appropriate trans -tetrahydrobromoacetate precursors.

The concomitant synthesis of dibenz(a,c)anthracene 1,2-oxide (8) and benz(a)anthryl (5,6-f) oxepine (9) from a common dibromoacetate precursor, and photoisomerization of arene oxide (8) to the oxepine (9) via an oxygen walk mechanism occurs in accord with predictions.

The concomitant synthesis of dibenz(a,c)anthracene 1,2-oxide (8) and benz(a)anthryl (5,6-f) oxepine (9) from a common dibromoacetate precursor, and photoisomerization of arene oxide (8) to the oxepine (9) via an oxygen walk mechanism occurs in accord with predictions.

The synthesis of arene oxides and oxepines, and the unexpectedly facile rearrangement of a range of non-K- and bay-region arene oxides of polycyclic aromatic hydrocarbons to isolable isomeric oxepines via a photochemical oxygen walk pathway is reported; oxepine formation can be predicted from PMO calculations which indicate the associated loss of resonance energy during the oxygen walk process.