The [4 + 2] cyclization/retro-Mannich reaction cascade of para-quinone methide derivatives with Pd-containing 1,4-dipoles.

The first [4 + 2] cyclization/retro-Mannich reaction cascade of para-quinone methides with Pd-containing 1,4-dipoles generated in situ from vinyl benzoxazinanones has been established. The corresponding rearrangement products were obtained in generally good to excellent yields (up to 92% yield). This reaction represents the first example of C[double bond, length as m-dash]C double bond cleavage of para-quinone methides, which will greatly enrich the chemistry of quinone methides.