Mechanistic Investigations of Palladium-Catalyzed Allylic Fluorination
作者:Matthew H. Katcher、Per-Ola Norrby、Abigail G. Doyle
DOI:10.1021/om401240p
日期:2014.5.12
A computational and experimental approach was employed to study the mechanism of the palladium(0)-catalyzed fluorination of allylic chlorides with AgF as fluoride source. Our findings indicate that an allylpalladium fluoride is a key intermediate necessary for the generation of both the nucleophile and electrophile. Evidence was also obtained to support a homobimetallic mechanism in which C–F bond
allyl ethyl carbonates with isocyanides in the presence of a catalytic amount of Pd(OAc)2 provided ketenimines through β‐hydride elimination of the allyl imidoylpalladium intermediates. The insertion of the isocyanide into the π‐allyl Pd complex proceeded via an unusual η1‐allyl Pd species. The resulting ketenimines were hydrolyzed to β,γ‐unsaturated carboxamides during purification by flash column chromatography