Sorbates from 1,1-Dialkylsubstituted Alkenes and 3-Haloacrylic Esters via Pd(II)-Isohypsic Catalysis: Focus on Terpenes

Limonene and other 1,1-dialkylsubstituted alkenes undergo a regioselective Pd(II)-catalyzed C–H/C–X coupling with (E) and (Z)-3-bromoacrylates affording 4,4-disubstituted sorbate derivatives as mixtures of geometrical isomers (16 examples). This coupling, unknown to date for the synthesis of 1,3-dienes, follows a mechanism distinct from the well-known Mizoroki–Heck, and works where the Mizoroki–Heck fails. Density functional theory (DFT) computations allowed to propose a plausible mechanism for this transformation.