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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.

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.