title: Palladium(II)-catalyzed direct carboxylation of alkenyl C-H bonds with CO2.
abstract: Pd-catalyzed direct carboxylation of alkenyl C-H bonds with carbon dioxide was realized for the first time. Treatment of 2-hydroxystyrenes and a catalytic amount of Pd(OAc)2 with Cs2CO3 under atmospheric pressure of CO2 afforded corresponding coumarins in good yield. Furthermore, isolation of the key alkenylpalladium intermediate via C-H bond cleavage was achieved. The reaction was proposed to undergo reversible nucleophilic addition of the alkenylpalladium intermediate to CO2.
authors.affiliation: Department of Chemistry, Tokyo Institute of Technology, O-okayama, Tokyo 152-8551, Japan.
authors.forename: Kota
authors.initials: K
authors.lastname: Sasano
authors.forename: Jun
authors.initials: J
authors.lastname: Takaya
authors.forename: Nobuharu
authors.initials: N
authors.lastname: Iwasawa