Efficient Construction of Tetracyclic 1,2,4‐Triazoline‐Fused Dibenzo[b,f][1,4]oxazepines through KI/TBHP‐Mediated [3+2] Annulation between DBO‐Imines and N‐Tosylhydrazones.

The KI/TBHP (tert‐butyl hydroperoxide) promoted [3+2] annulation between dibenzo[b,f][1,4]oxazepine‐imines (DBO‐Imines) and N‐tosylhydrazones under mild conditions has been developed, affording a direct and high atom‐economical preparation for tetracyclic 1,2,4‐triazoline‐fused dibenzo[b,f][1,4]oxazepines (DBOs) in good to excellent yields. This procedure could tolerate a wide range of functional groups and could also be conveniently conducted on a gram‐scale reaction, even in a one‐pot fashion. The produced 1,2,4‐triazoline‐fused DBOs could be easily converted into biologically interesting 1,2,4‐triazolo‐fused DBOs under the action of NBS (N‐bromosuccinimide). [ABSTRACT FROM AUTHOR]