“…Significantly, the 1 H NMR (CDCl 3 ) of H 3 and H 4 in 3 (3.77 and 4.64, J 3,4 = 6.6 Hz) is in full accord with that reported for the corresponding H 3 and H 4 in 1a (3.92 and 4.98 J 3,4 = 6.5 Hz) . It was previously found experimentally 4,5 and theoretically, via molecular orbital calculations, , that K-region PAH-episulfides are, thermodynamically, more stable toward sulfur extrusion than their bay-region isomers. This, together with the relatively higher thermodynamic stability of the episulfides with the higher aromatic character of the ring system, is in accord with the instability of 3 .…”