Pd-Catalyzed Coupling Cyclization of δ, ε-Alkenyl Oxime toward Access to 1,2-Oxezapines

The Pd-catalyzed coupling cyclization of delta,epsilon-alkenyl oxime with (hetero)aryl and halides is presented, which affords seven membered N,O-heterocycle, tetrahydro-1,2-oxezapines, in moderate to good yields. DFT calculation favors an outer-sphere anti-oxypalladation pathway and provides key insights on the reaction mechanism. The reaction represents an unprecedented example of seven-membered ring formation by heterocyclization.

Automated summary

This paper presents the Pd-catalyzed coupling cyclization of delta,epsilon-alkenyl oxime with (hetero)aryl and halides, which results in the synthesis of seven-membered N,O-heterocycles, tetrahydro-1,2-oxezapines, in moderate to good yields. DFT calculation supports an outer-sphere anti-oxypalladation pathway and provides important insights into the reaction mechanism. This reaction represents an unprecedented example of heterocyclization leading to the formation of a seven-membered ring.