Novel ring enlargement of lactams via quinazolinone annelation. A facile route to benzoannelated large-membered cyclic 1,5-diamines

A novel route to benzoannelated large-membered cyclic 1,5-diamines from lactams is described. Thus, n-membered lactams 1 were N-acylated by o-azidobenzoyl chloride 5 to afford the corresponding imides 4. These were treated with tributylphosphine and underwent an intramolecular aza-Wittig reaction to give n-membered ring-fused quinazolinones 2 in 84-96% yield. By reductive cleavage of 2 with BH 3 •THF, (n+4)-membered cyclic diamines 3 were obtained in 52-95% yield