Kinetically Controllable Construction of Nine-Membered Carbocycles via Pd-Catalyzed Decarboxylative Cycloaddition

A kinetically controllable strategy toward the construction of otherwise challenging nine-membered carbocycles is reported. This Pd-catalyzed decarboxylative procedure utilizes vinyl methylene cyclic carbonates as the C5-dipole and allylidenemalononitriles as C4-building blocks. The protocol features user-friendly operations with controllable regioselectivity and generates CO2 as the sole byproduct. The formation of synthetically valuable and thermodynamically favored seven-membered carbocycles was also investigated.