An efficient one-pot construction of functionalized 3-methylene-5-phenyl-1,2,3,4-tetrahydropyridine derivatives via palladium-catalyzed cyclization-Heck reaction of allenamides has been described. The 3-methylene-5-phenyl-1,2,3,4-tetrahydropyridine derivatives feature a nonconjugated diene, including one endo-enamine and one exocyclic double bond, which could be used for further transformation. Both aryl and vinyl halides performed very well under the standard conditions, delivering the corresponding products efficiently.

Electrophilic Amination The task of realizing selective assembly of amines from readily available precursors has become a prominent objective in organic chemistry. The importance of C−N bond construction by application of O-benzoylhydroxylamines in transition-metal-catalyzed electrophilic amination has led to the rapid development of this field. In their Review article on page 2481 ff., Q. Liu, H. Liu and colleagues describe the recent advances of O-benzoylhydroxylamines involved in electrophilic amination catalyzed by transition metals. Several pioneering studies and some of the relevant mechanisms are discussed.

AbstractTransition-metal-catalyzed electrophilic amination has been developed into a powerful tool for C−N bond construction. So far, O-benzoylhydroxylamines are the most widely used electrophilic aminating reagents. Herein, we summarize the recent advances of O-benzoylhydroxylamines involved in electrophilic amination catalyzed by transition metals. Several pioneering studies and some of the relevant mechanisms are discussed in this review.

A new type of cascade metallo-ene/Suzuki coupling reaction of allenamides catalyzed by palladium is described. A variety of polyfunctionalized 2,3-dihydropyrrole derivatives, which are important structural motifs for bioactive molecules, were furnished with excellent yields. Two new Csp3–Csp2 bonds were constructed in one pot efficiently. The reductive elimination from π-allyl palladium complex presented excellent regioselectivity to the terminal C1 position. The unique terminal alkene was one of the most easily functionalized groups, providing these molecules with a potential transformation to much more complicated molecules.

A new type of cascade metallo-ene/Suzuki coupling reaction of allenamides catalyzed by palladium is described. A variety of polyfunctionalized 2,3-dihydropyrrole derivatives, which are important structural motifs for bioactive molecules, were furnished with excellent yields. Two new Csp3–Csp2 bonds were constructed in one pot efficiently. The reductive elimination from π-allyl palladium complex presented excellent regioselectivity to the terminal C1 position. The unique terminal alkene was one of the most easily functionalized groups, providing these molecules with a potential transformation to much more complicated molecules.

This work reports the copper(I)-catalyzed 5-exo-trig radical cyclization/borylation of alkyl halides bearing an alkene moiety, during which a C–C bond and a C–B bond were formed in one step. Various functionalized pyrrolidine derivatives bearing a quaternary carbon center were obtained, and they showed good functional group tolerance and high chemoselectivity. This transformation was highly efficient and could be finished in 20 minutes. A radical mechanism has been proposed.

A palladium-catalyzed intramolecular hydrocarbonation of unactivated alkenes was achieved, in which toluene is used as a hydrogen donor for the first time. The radical transfer hydrogenation is designed and realized based on the Bond Dissociation Energy (BDE) value. A toluene derivative, which is cheap, readily available and easy to handle, serves as a new hydrogen donor in radical involved reactions, providing a novel and promising perspective for future reductive reactions.

A Pd(II)/(IV)-catalyzed oxidative isomerization of propargylic acetates developed for the synthesis of polysubstituted alkenyl acetates is described. The reductive elimination of alkenyl Csp2–OAc bonds from PdIV intermediates is achieved. Mechanistic studies indicate that the reaction mechanism consists of trans acetoxypalladation of a triple bond, isomerization, oxidative addition with PhI(OAc)2 and alkenyl C–OAc bond reductive elimination.

A new type of palladium-catalyzed 6-endo-selective alkyl-Heck reaction of unactivated alkyl iodides has been described. This strategy provides efficient access to a variety of 5-phenyl-1,2,3,6-tetrahydropyridine derivatives, which are important structural motifs for bioactive molecules. This process displays a broad substrate scope with excellent 6-endo selectivity. Mechanistic investigations reveal that this alkyl-Heck reaction performs via a hybrid palladium-radical process.

A palladium-catalyzed intramolecular hydrocarbonation of unactivated alkenes was achieved, in which toluene is used as a hydrogen donor for the first time. The radical transfer hydrogenation is designed and realized based on the Bond Dissociation Energy (BDE) value. A toluene derivative, which is cheap, readily available and easy to handle, serves as a new hydrogen donor in radical involved reactions, providing a novel and promising perspective for future reductive reactions.

A new type of cascade metallo-ene/Suzuki coupling reaction of allenamides catalyzed by palladium is described. A variety of polyfunctionalized 2,3-dihydropyrrole derivatives, which are important structural motifs for bioactive molecules, were furnished with excellent yields. Two new Csp3–Csp2 bonds were constructed in one pot efficiently. The reductive elimination from π-allyl palladium complex presented excellent regioselectivity to the terminal C1 position. The unique terminal alkene was one of the most easily functionalized groups, providing these molecules with a potential transformation to much more complicated molecules.

A new type of cascade metallo-ene/Suzuki coupling reaction of allenamides catalyzed by palladium is described. A variety of polyfunctionalized 2,3-dihydropyrrole derivatives, which are important structural motifs for bioactive molecules, were furnished with excellent yields. Two new Csp3–Csp2 bonds were constructed in one pot efficiently. The reductive elimination from π-allyl palladium complex presented excellent regioselectivity to the terminal C1 position. The unique terminal alkene was one of the most easily functionalized groups, providing these molecules with a potential transformation to much more complicated molecules.

A Pd(II)/(IV)-catalyzed oxidative isomerization of propargylic acetates developed for the synthesis of polysubstituted alkenyl acetates is described. The reductive elimination of alkenyl Csp2–OAc bonds from PdIV intermediates is achieved. Mechanistic studies indicate that the reaction mechanism consists of trans acetoxypalladation of a triple bond, isomerization, oxidative addition with PhI(OAc)2 and alkenyl C–OAc bond reductive elimination.