Palladium-catalyzed ring-closing reaction of enynols with aminals via methylene transfer and C–N bond activation

The aminomethyl cyclopalladated complex is identified as a key intermediate for promoting the C–N bond activation of tertiary amines via reductive elimination and oxidative addition sequence. This strategy has enabled a palladium-catalyzed ring-closing reaction of enynols with aminals via methylene transfer and C–N bond activation, which provides rapid access to densely functionalized O-heterocycle containing allenic amines. The dual roles of the cyclopalladated complex, first as an aminomethylene-carrying reagent and then as a catalyst for C–N bond activation, have enabled a rare cascade redox-neutral methylene transfer and cyclization process that can simultaneously construct O-heterocycle framework and allenic amine functionality.