Palladium catalyzed divergent cycloadditions of vinylidenecyclopropane-diesters with methyleneindolinones enabled by zwitterionic π-propargyl palladium species

An in situ generated unprecedented zwitterionic π-propargyl palladium species in a switchable process between (3+2) and (4+2) cycloadditions can be achieved by changing the phosphine ligand.