Gram-scale selective telomerization of isoprene and CO₂ toward 100% renewable materials

Carbon dioxide (CO₂) is an ideal chemical feedstock due to its abundance, low cost, low toxicity and its role as a greenhouse gas. Telomerization with butadiene give rise to functional small molecules and polymers with significant CO₂ content, but the fossil origin of the olefin offsets sustainability benefits. Here, we present a palladium-catalyzed telomerization of CO₂ with isoprene, two of the most prevalent organic compounds in the atmosphere, yielding "COOIL", an ideally 100% renewable δ-lactone containing 24 wt% CO₂, with high selectivity and turnover numbers above 100. A combination of a Pd catalyst, acetate, and controlled water promoted selectivity and conversion. Density functional theory calculations reveal reductive elimination as the rate-limiting and selectivity-determining step, preceded by isoprene dimerization. The head-tail pathway is the kinetic pathway while the tail-tail product is the thermodynamic product. This functionalized lactone also shows promise for polymerization under Lewis acid-promoted conditions, opening avenues for sustainable polymers from CO₂ and bio-derived feedstocks.