Palladium-Catalyzed C8-H Acylation Of 1-naphthylamines

A facial and efficient protocol for palladium-catalyzed regioselective C8-H acylation of 1-naphthylamine derivatives with abundant and commercially available acyl chlorides has been developed(Scheme 1).Note that it proceeded smoothly under the standard condition without external oxidant.And the reaction exhibits broad functional group tolerance and could tolerate diverse electron-donating and-withdrawing substituents in the pyridine ring or the naphthalene moiety,generating the corresponding products in moderate to good yields.Both aromatic and ?,?-unsaturated acyl chlorides can also be effectively coupled with 1-naphthylamines.The addition of radical scavengers such as 2,2,6,6-tetramethyl-1-piperidinyloxy(TEMPO)and 2,6-di-tert-butyl-4-methylphenol(BHT)did not inhibit this reaction,therefore this reaction maybe not involve a radical process.Moreover,the picolinamide moiety as a bidentate directing group likely plays a key role in this regioselective transformation according to the control experiments we conducted.