Abstract: Several aspects of the catalytic telomerization of 1, 3-butadiene and C 0 2 have been examined with the aims of studying the catalytic properties of reversible CO,-carrier complexes and of selectively producing the &lactone 2-ethylidene-6-hepten-5-olide (3). When using Pd (I1) complexes containing a cyclometalated ligand and a functional phosphine, only the specific C 0 2 carriers [(o-C6H4CH2NMe2) Pd (R2PC (C02Et)= C (0) ...