Stereochemical outcome of perhydro hexaazadibenzotetracene formation from trans-1,2-diaminocyclohexane

A one-pot reaction between (±)-trans-1,2-diaminocyclohexane and glyoxal affords intermediate perhydro-1,6,7,12-tetraazatetracene whose further treatment with formaldehyde and (het)arylamines in the presence of YbCl₃·6H₂O gives 2,9-di(het)aryl substituted (3bR*,7aR*,10bR*,14aR*)-perhydro-2,3a,7b,9,10a,14b-hexaazadibenzo[fg,op]tetracenes with cis-junction of the cycles along the C(14c)–C(14d) bond.