Pd-Catalyzed Cyclization and Cyanation of Alkynone <i>O</i> -Methyloximes with <i>tert</i> -Butyl Isocyanide

A palladium-catalyzed cyclization and cyanation for synthesizing polyfunctionalized isoxazoles derivatives has been disclosed. The commercially available tert -butyl isocyanide has been proved as an efficient “CN” source in this transformation. This new protocol exhibits broad substrate compatibility, leading to diverse nitrile-substituted isoxazoles in moderate to good yields from readily available building blocks alkynone O -methyloximes. A possible catalytic cycle is proposed, involving a tandem sequence of Pd II -initiated trans -oxypalladation, isocyanide migratory insertion, β- tert -butyl elimination.