ChemInform Abstract: Highly Regioselective α‐Arylation of Coumarins via Palladium‐Catalyzed C—H Activation/Desulfitative Coupling.

Abstract

A novel regioselective α‐arylation of coumarins with readily available arenesulfonyl chlorides via palladium‐catalyzed direct C—H functionalization under mild reaction conditions is described.

Natural source, bioactivity and synthesis of 3-Arylcoumarin derivatives

“…Coumarin substitution methods are available as follows. Direct arylation of coumarins in the presence of metallopalladium catalysis, using inexpensive sulphonyl or sulphite, constructs biologically significant 3-arylcoumarins and precludes prefunctionalization of coumarins 84 , Versatile palladium-catalysed C–H olefination of (hetero)arenes at room temperature 85 . The regioselective arylation of coumarins with phenylhydrazine 86 , 87 or phenylboronic acid 88 , 89 under transition metal-free conditions gives 3-aryl coumarins.…”

Arylation of Carbonyl Compounds via Photoredox Catalysis

“…The first was based on the use of arylsulfonyl chlorides 248 with 262, with no functionalization at C3 position. 217 The copper salt was used as oxidant in 1.0 equivalent, but the author did not conclude its real role in the mechanism.…”