Regioselective transition metal-free acylation of coumarins via cross-dehydrogenative coupling reaction of coumarins and aldehydes

Recent Developments in Transition Metal‐Free Cross‐Dehydrogenative Coupling Reactions for C–C Bond Formation

“…The quenching of reaction in presence of TEMPO confirmed the radical mechanism of the reaction. [41] Scheme 52. Coupling of coumarins with aldehydes.…”

“…Adib et al also reported a K 2 S 2 O 8 /Aliquat 336 mediated regioselective cross‐dehydrogenative coupling of coumarins and aldehydes to afford acylated coumarins under transition metal‐free conditions (Scheme 52). [ 41 ] The reaction worked well with variously substituted aromatic aldehydes and derivatives of coumarins to afford the corresponding coupled products in good to excellent yields. Both electron‐donating and withdrawing groups were well tolerated under the optimized reaction conditions.…”

Synthesis, Spectroscopic Characterization, Single-Crystal Structure, Hirshfeld Surface Analysis, and Antimicrobial Studies of 3-Acetoxy-2-methylbenzoic Anhydride

“…Anhydrides are compounds with two carbonyl groups attached to the same oxygen. There are many methods for synthesizing various symmetrical and unsymmetrical anhydrides in the literature. − The most common anhydrides in organic chemistry are those derived from carboxylic acids and the dehydration of carboxylic acids in the presence of dehydrating reagents like carbodiimides, thionyl chlorides, and isocyanates . In addition, the synthesis of anhydrides has been reported by the acylation of acyl halides and anhydrides with carboxylates …”

The Latest Advancements in the Acylation Reactions via Cross-Dehydrogenative Coupling and/or Metal Catalysts

“…When TEMPO is added, no product could be obtained stating that this pathway was in free radical nature (Scheme 13). The proposed mechanism of TBHP/TFA mediated oxidative cross-dehydrogenative coupling of N-heterocycles with aldehydes.Most recently, the acylation of coumarins via CDC approach using aldehydes to serve as acylating agents was investigated in detail by Adib group(35), Qu(36) and Zhou (37). On top of these studies, Duan and co-workers illustrated the Ag-catalyzed diacylation of coumarins using oxocarboxylic acids as the acyl sources(38).…”