Mapping Ambiphile Reactivity Trends in the Anti-(Hetero)annulation of Non-Conjugated Alkenes via PdII /PdIV Catalysis.

ABSTRACT

In this study, we systematically evaluate different ambiphilic organohalides for their ability to participate in anti-selective carbo- or heteroannulation with non-conjugated alkenyl amides under PdII /PdIV catalysis. Detailed optimization of the reaction conditions has led to protocols for synthesizing tetrahydropyridines, tetralins, pyrrolidines, and other carbo/heterocyclic cores via [n+2] (n=3-5) (hetero)annulation. Expansion of scope to otherwise unreactive ambiphilic haloketones through PdII /amine co-catalysis is also demonstrated. Compared to other annulation processes, this method proceeds via a distinct PdII /PdIV mechanism involving Wacker-type directed nucleopalladation. This difference results in unique reactivity and selectivity patterns, as revealed through assessment of reaction scope and competition experiments.