Rhodium‐Catalyzed Functionalization and Annulation of N‐Aryl Phthalazinediones with Allyl Alcohols

Abstract A direct ortho ‐Csp 2 ‐H acylalkylation of 2‐aryl‐2,3‐dihydrophthalazine‐1,4‐diones with unsubstituted and substituted allyl alcohols is achieved in high yields through Rh(III)‐catalyzed C−H bond activation process. The additional employment of Cu(OAc) 2 ⋅2H 2 O as an oxidant detour the reaction towards [4+1] annulation, producing 13‐(2‐oxopropyl)‐13 H ‐indazolo[1,2‐ b ]phthalazine‐6,11‐diones in moderate yields. Interestingly, Lawesson's reagent‐mediated conditions accomplished intramolecular cyclization in ortho ‐(formylalkylated)‐2,3‐dihydrophthalazine‐1,4‐diones to produce diazepino[1,2‐ b ]phthalazine‐diones in moderate yields. Furthermore, allyl alcohol showcased distinct reactivity in presence of different additives to produce ortho ‐allylated, oxidative and non‐oxidative [4+2] annulated products.