Base-Promoted 5- exo - dig Cyclization of o -Alkynylamides or 2-En-4-ynamides with CO 2 toward Fully Substituted Acrylates.

A base-promoted sequential cyclization and carboxylation of o -alkynylamides or 2-en-4-ynamides with CO 2 has been achieved with high efficiency, stereoselectivity, and regioselectivity. This approach begins with 5- exo - dig cyclization followed by trapping the resulting vinyl anion with CO 2 and MeI, which provides a convenient access to diverse cyclic and fully substituted acrylates with CO 2 as the carboxylic source.