A highly efficient Pd/CuI-catalyzed oxidative alkoxycarbonylation of α-olefins to unsaturated esters

- This is a new protocol for the alkoxycarbonylation of α-olefins to unsaturated esters.
- Pd/C, Pd/Al2O3 and Pd/CaCO3, in conjunction with CuI, are the most active catalysts.
- A variety of alcohols and olefins were employed as starting materials.
- Experimental evidences account for a homogeneous palladium-catalyzed reaction.
- Commercial cinnamate derivatives were prepared in good to excellent yields.

A new protocol for the alkoxycarbonylation of α-olefins to the corresponding unsaturated esters has been developed. Differently substituted styrenes were selectively converted to cinnamate derivatives, via CH bond functionalization. Various palladium sources, including heterogeneous ones, in combination with CuI exhibited a high catalytic efficiency using oxygen as the most cheap oxidant. Monocarbonylated products were obtained in good yields and high chemoselectivity working with a low CO pressure (2 atm) and an excess of air (35 atm) avoiding in this way explosion risks. Commercial cinnamate derivatives were prepared in good to excellent yields by this very simple one-pot procedure.

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