Activation of Alcohols with Carbon Dioxide: Intermolecular Allylation of Weakly Acidic Pronucleophiles

The direct coupling of allyl alcohols with nitroalkanes, nitriles, and aldehydes using catalytic Pd­(PPh3)4 has been accomplished via activation of C–OH bonds with CO2. The in situ formation of carbonates from alcohols and CO2 facilitates oxidative addition to Pd to form reactive π-allylpalladium intermediates. In addition, the formation of a strong base activates nucleophiles toward the reaction with the π-allylpalladium electrophile. Overall, this atom economical reaction provides a new C–C bond without the use of an external base and generates water as the only byproduct.