An efficient synthesis of N-acyl enamine amides via palladium-catalyzed alkene C–H activation and isocyanide insertion has been developed. The reaction was realized with good regioselectivity through directing-group-assisted alkenyl C(sp2)–H bond carboxamidation under mild conditions. A facile pathway to β-amino amides was achieved via reduction of the synthesized N-acyl enamine amides.
An unprecedented tandem carbonylation/aminocarbonylation triggered by palladium-catalyzed enantioselective Heck-type exocyclopalladation delivering chiral heterocyclic α-ketoamides has been developed. The uncommon double CO insertion into the σ-alkylpalladium intermediate takes place selectively under atmospheric pressure of CO using alkylamine as the nucleophile. Unique structures hybridizing alkyl α-ketoamides with indolin-2-one containing a C3 all-carbon quaternary stereogenic center and 5,7-dihydro-6H-dibenzo[b,d]azepin-6-one containing a thermodynamically stabilized stereogenic biaryl axis are produced in good yields with excellent enantio- and/or diastereoselectivities.
An efficient access to amino substituted phenanthridine and isoquinoline derivatives, through palladium-catalyzed C(sp 2 )–H aminoimidoylation, has been developed.
An efficient synthesis of pyridoisoquinolinones, through Pd-catalyzed carbonylative annulation of 2-benzylpyridines, has been developed. The pyridinyl moiety in the substrate acts as both a directing group and an internal nucleophile for sp2 C–H activation and pyridocarbonylation. The ready availability of 2-benzylpyridines as well as the operational practicality makes this transformation potentially useful for the synthesis of analogues of protoberberine alkaloids.