Pd-Catalyzed C(sp 2 )-H/C(sp 2 )-H Coupling of Limonene.

Limonene undergoes a regioselective Pd(II)-catalyzed C(sp ² )-H/C(sp ² )-H coupling with acrylic acid esters and amides, α,β-unsaturated ketones, styrenes, and allyl acetate, affording novel 1,3-dienes. DFT computations gave results in accord with the experimental results and allowed for the formulation of a plausible mechanism. The postfunctionalization of one of the coupled products was achieved via a large-scale Sonogashira reaction conducted under micellar catalysis.