Palladium-Catalyzed Narasaka-Heck Carbonylation Using Cr(CO)6 as Carbonyl Source: Access to Ester-Containing Pyrrolines.

An unprecedented Pd-catalyzed CO gas-free Narasaka-Heck carbonylation using Cr(CO)6 as a convenient carbonyl source has been developed for the step-economic construction of ester-containing pyrrolines. Notably, this method overcomes the limitations of conventional radical pathways, enabling compatibility with phenol-type substrates and 1,1-disubstituted alkenes, while avoiding the use of high-pressure CO gas. The protocol features operational simplicity, a broad substrate scope, and excellent functional group tolerance, and the resulting products are amenable to diverse transformations.