Palladium/Norbornene‐Catalyzed Sequential ortho‐Acylation and ipso‐Alkenylation with Carboxylic Acid: Access to Polysubstituted Aryl Ketones

Abstract

Herein a palladium/norbornene‐catalyzed sequential ortho‐acylation and ispo‐alkenylation for access to polysubstituted aryl ketones has been developed. By exploiting dicyclohexylcarbodiimide (DCC) as activator, aryl with electron‐donating or electron‐withdrawing functionalities, alkyl, and heteroaryl carboxylic acids were compatible in this transformation, affording the desired products in decent to good yields.

ortho‐Acylation of Aryl Iodides Enabled with Imides via Palladium/Norbornene/CuI Catalysis

“…Moreover, carbamic chlorides [22] and selenoates [23] have also been used as acylating reagents in this chemistry (Scheme 1b). Inspired by the works of those research groups, our group used carboxylic acids as electrophile to prepare polysubstituted aryl ketones with the asssitance of dicyclohexylcarbodiimide (DCC) (Scheme 2a) [24] . Subsequently, we exploited bench‐stable triazine esters as acylating reagents to achieve an ortho ‐acylation/ ipso ‐alkenylation cascade via cleavage of the C(O)−O bond cleavage of the ester (Scheme 2b) [25] .…”

“…Inspired by the works of those research groups, our group used carboxylic acids as electrophile to prepare polysubstituted aryl ketones with the asssitance of dicyclohexylcarbodiimide (DCC) (Scheme 2a). [24] Subsequently, we exploited benchstable triazine esters as acylating reagents to achieve an ortho-acylation/ipso-alkenylation cascade via cleavage of the C(O)À O bond cleavage of the ester (Scheme 2b). [25] In our continuous research interest, we envisioned the possibility of Pd/NBE-catalyzedsynthesis of aryl ketones using imides as ortho-acylating reagents, which have been used in Pd-catalyzed acylation of aromatic compounds through direct CÀ H activation [26] (Scheme 2c).…”

Acid‐Promoted Expeditious Syntheses of Aminated Dibenzosultams via Palladium/Norbornene Cooperatively Catalysed C−H Amination/Arylation

“…Divergent synthetic methods for assemble of sultams have been established by the group of Zhu, [24b] Wu, [25b] Ma, [25c] Kanai, [26b] and Lei, [26c] including transition‐metal or lewis acid‐catalyzed processes, [24] metal‐free oxidative annulation strategy, [25] and intermolecular cyclization [26] . Inspired by these reports and in continuation of our research interests [11d,e] in Pd/NBE‐catalyzed reaction, we are intrigued whether it would be possible to synthesize benzosultams motif through Catellani‐type reaction using aryl halide with sulfoamide group as linking group, which has not been reported to date. Herein we reported our newly disclosed protocol to access aminated bensosultams through sequential ortho ‐amination/ ipso ‐C−H bond arylation with sulfoamide‐tethered aryl iodide via palladium/norbornene coorperative catalysis (scheme 1d).…”