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

• Published in: Chemistry, an Asian journal an Asian journal, 2024-12, Vol.19 (23), p.e202400711-n/a
• Main Authors: Naharwal, Sushma, Dinkar Kharat, Narendra, Bajaj, Kiran, Panda, Siva S, Sakhuja, Rajeev
• Format: Article
• Language: English
• Subjects: Alcohols; Annulation; Aromatic compounds; Catalysis; Chemical reactions; C−H activation; Diketones; Functionalization; Hydrogen bonds; Organic chemistry; Oxidizing agents; Reagents; Rhodium; Transition-metal
• ISSN: 1861-4728; 1861-471X; 1861-471X
• DOI: 10.1002/asia.202400711

A direct ortho‐Csp2‐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⋅2H2O as an oxidant detour the reaction towards [4+1] annulation, producing 13‐(2‐oxopropyl)‐13H‐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. Expedite strategy for installing acylalkyl/formylalkyl groups at ortho‐position of 2‐aryl‐2,3‐dihydrophthalazine‐1,4‐diones using allyl alcohols under Rh(III)‐catalysis. Slightly modified Cu(OAc)2.2H2O‐mediated conditions foster [4+1] annulation, while several fused and functionalized products were obtained by using unsubstituted allyl alcohol under Rh‐catalyzed additive‐mediated conditions.