Palladium-catalyzed [6 + 4] cycloaddition with π-allyl all-carbon 1,6-dipole for the synthesis of ten-membered heterocycles

Abstract

This paper presents the design and synthesis of a novel α,α-diester-δ-vinylvalerolactone, utilized as a new all-carbon dipolar precursor in a palladium-catalyzed [6 + 4] cycloaddition reaction with azadienes. The reaction results in the formation of a ten-membered heterocycle with up to 95% yield and exclusive regioselectivity. The method features mild reaction conditions and excellent functional group tolerance. The practical applicability of the synthesis is demonstrated through scale-up reactions and further transformation.