Remote Construction of N‐Heterocycles via 1,4‐Palladium Shift‐Mediated Double C−H Activation
摘要:
AbstractIn the past years, Pd0‐catalyzed C(sp3)−H activation provided efficient and step‐economical methods to synthesize carbo‐ and heterocycles via direct C(sp2)−C(sp3) bond formation. We report herein that a 1,4‐Pd shift allows access to N‐heterocycles which are difficult to build via a direct reaction. It is shown thato‐bromo‐N‐methylanilines undergo a 1,4‐Pd shift at theN‐methyl group, followed by intramolecular trapping by C(sp2)−H or C(sp3)−H activation at another nitrogen substituent and remote C−C bond formation to generate biologically relevant isoindolines and β‐lactams. The product selectivity is influenced by the employed ligand, with NHCs favoring the product of remote C−C coupling against products arising from direct C−C coupling and N‐demethylation.
General Synthesis of <i>N</i>-Alkylation of Amines with Secondary Alcohols via Hydrogen Autotransfer
作者:Murugan Subaramanian、Siba P. Midya、Palmurukan M. Ramar、Ekambaram Balaraman
DOI:10.1021/acs.orglett.9b02990
日期:2019.11.15
Direct catalytic N-alkylation of amines with secondary alcohols via hydrogen autotransfer (HA) strategy is very challenging and has been scarcely reported, even under precious metal catalysis. Herein, an efficient N-alkylation of amines, including benzylamines using secondary alcohols as alkylating agents, is reported. This reaction is catalyzed by a molecularly defined NNN-Ni(II) pincercomplex, and