Palladium‐promoted Cyclization of Tetra‐alkylated 1‐Arylazonaphthalenes to 2‐Aryl‐benzo[<i>g</i>]indazoles

Abstract

Abstract 1‐Arylazonaphthalenes with all the potential cyclopalladation sites (one peri ‐ and three ortho ‐positions) substituted by methyl or ethyl groups react with stoicheiometric or catalytic amounts of sodium tetrachloropalladate(II) to the corresponding 2‐arylbenzo[ g ]indazoles. Possible mechanisms for the catalytic cyclization reaction are proposed.