Abstract
We recently achieved ortho-alkylation of iodoarenes utilizing a dual-ligand catalytic system that effectively
combines palladium/olefin ligand cooperative catalysis with reversible C(sp2)–I reductive elimination enabled by a bulky trialkylphosphine ligand. Through careful
mechanistic investigations, we confirmed the compatibility of the crucial steps involved
in this process by isolating key organometallic intermediates and studying the stoichiometry
of their transformations. By utilizing this protocol, we successfully achieved the
ortho-alkylation of a variety of iodoarene substrates, thereby expanding the scope of applications
for Catellani-type reactions. This study showcases the synthetic potential of the
Pd/olefin ligand cooperative system as an innovative complement to established Pd/norbornene
catalysis. In this Synpacts article, we present the conceptual framework underpinning
this reaction and detail the key aspects of its development.
1 Introduction
2 Research Background
2.1 The Catellani Reaction: Pd/Norbornene Catalysis
2.2 Cooperative Cycloolefin Ligands for the Catellani-Type Reactions
2.3 C–X Reductive Elimination on Pd Center
3 Development of the Reaction
3.1 Proof-of-Concept by Stoichiometric Reactions
3.2 Substrate Scope and Synthetic Applications
4 Conclusion
Key words
ortho-alkylation - iodoarene - reductive elimination - cooperative olefin ligand - palladium
catalysis - Catellani reaction