Catalytic intramolecular 2-(4-alkenyl)allylpalladium insertions

Pd(O)-catalyzed cyclizations of 1-acetoxy-2-methylene-6-heptenes(3 → 4, 18 → 19) are consistent with a allylpalladium/olefin insertion involving a metal-transfer to the distal alkene terminal. Cyclization 7 → 8 exemplifies a new stereocontrolled access to exocyclic trisubstituted alkenes which indicates a C,C-bond formation at the less substituted allylpalladium terminal thus showing a regio- and stereochemistry opposite to the type-II-magnesium-ene process 12 → 14