B(C6F5)3-Catalyzed tandem cyclization/hydrosilylation for the step-economical construction of 1,2,3,4-tetrahydroquinoxalines from readily available starting materials has been developed.

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A rhodium(III)‐catalyzed direct ortho CH bond olefination of arenes, including but not limited to benzamides, arylpyridines and indoles, with a variety of unactivated aliphatic olefins has been developed. In the presence of catalytic amounts of dichloro(pentamethylcyclopentadienyl)rhodium(III) dimer {[Cp*RhCl2]2}, copper(II) acetate monohydrate [Cu(OAc)2⋅H2O] and silver hexafluoroantimonate(V) (AgSbF6), the coupling reaction occurred efficiently to afford the ortho‐olefinated linear products in good to excellent yields with high regio‐ and stereoselectivities, and a range of functional groups in both coupling partners is compatible with the reaction conditions. This protocol relies on the use of directing groups, and the addition of AgSbF6 as additive is crucial for the catalysis. This new method expands the scope of rhodium(III)‐catalyzed direct CH bond olefination of arenes, and provides a rapid access to useful linear arylation products of unactivated olefins.magnified image

The first B(C 6 F 5 ) 3 -catalyzed deoxygenative reduction of amides into the corresponding amines with readily accessible and stable ammonia borane (AB) as a reducing agent under mild reaction conditions is reported. This metal-free protocol provides facile access to a wide range of structurally diverse amine products in good to excellent yields, and various functional groups including those that are reduction-sensitive were well tolerated. This new method is also applicable to chiral amide substrates without erosion of the enantiomeric purity. The role of BF 3 · OEt 2 co-catalyst in this reaction is to activate the amide carbonyl group via the in situ formation of an amide-boron adduct.

Co(III)-catalyzed highly regio-and stereoselective direct C6 olefination of 2-pyridones with alkynes has been developed with the assistance of chelation. Upon variation of the reaction conditions, 2-pyridones react well with diaryl alkynes via a C6 olefination/directing group migration pathway to give the tetrasubstituted 6-vinyl-2-pyridones, but the C6−H olefination with terminal alkynes works effectively to afford only the C6-olefinated 2-pyridones. A judicious choice of a solvent and an additive is crucial for catalysis. The protocols feature 100% atom economy, excellent site selectivity, high stereoselectivity, an ample substrate scope, and good compatibility of functional groups. Synthetic applications are demonstrated, and experimental studies and density functional theory calculations are conducted to gain mechanistic insight into the two transformations.