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.