Intramolecular Palladium(II)-catalyzed 6-endo C-H alkenylation directed by the remote N-protecting group. Mechanistic insight and application to the synthesis of dihydroquinolines

A protocol for the Pd(II)-catalyzed C-H alkenylation reaction of substituted N-allylanilines via an unusual 6-endo process has been developed. A DFT study of the mechanistic pathway has shown that the coordination of the remote protecting group to the palladium center is determinant for the control of the regioselectivity in favor of the 6-endo process. The reaction would proceed via prior activation of the alkene. This procedure constitutes a mild and efficient method for the synthesis of 1,4- dihydroquinoline derivatives from simple and readily accessible substrates.Ministerio de Economía y Competitividad (CTQ2016-74881-P; CTQ2016-78083-P) // Gobierno Vasco (IT1045-16

Pd(II)-Catalyzed Fujiwara-Moritani Reactions for the Synthesis and Functionalization of Substituted Coumarins.

[EN]Highly substituted coumarins, privileged and versatile scaffolds for bioactive natural products and fluorescence imaging, are obtained via a Pd(II)-catalyzed direct C–H alkenylation reaction (Fujiwara–Moritani reaction), which has emerged as a powerful tool for the construction and functionalization of heterocyclic compounds because of its chemical versatility and its environmental advantages. Thus, a selective 6-endo cyclization led to 4-substituted coumarins in moderate yields. Selected examples have been further functionalized in C3 through a second intermolecular C–H alkenylation reaction to give coumarin-acrylate hybrids, whose fluorescence spectra have been measured.Ministerio de Economía y Competitividad (FEDER CTQ2016-74881-P), Ministerio de Ciencia e Innovación (PID2019-104148GB-I00), and Gobierno Vasco (IT1045-16) are gratefully acknowledged for their financial support. A.C.-M. wishes to thank Gobierno Vasco for a grant. Technical and human support provided by Servicios Generales de Investigación SGIker (UPV/EHU, MINECO, GV/EJ, ERDF and ESF) is also acknowledged