PdCl₂/FeCl₂-Cataiyzed Cascade Cyclization Reaction Of Alkyones: The Synthesis Of Complicated Compounds Via C-H/C-C Bond Activation

In recent years, The research on alkynones has attracted considerable interests both ontheir synthesis and application. Especially on their utility as synthetic intermediates for thesynthesis of natural products1and heterocycles.2The urgent demands for their broadlyapplication has became a steadily increasing driving force for the continued research on thealkynones in both academia and industry. Compared with the outstanding achievements oftransition metal catalyzed C-C/C-H bond activations, we know little about the C-C bond andC-H bond activation of alkynones. In order to promote the broadly application of alkynones, itis necessary to develop a catalyst system for the C-C bond and C-H bond activation ofalkynones.Dual-metal catalysis, which presumably involves at least two cooperative catalyticcycles to furnish the synthesis of final products, has attracted much attentions. Palladiumcatalyzed cascade reactions have been demonstrated to be versatile tools for the synthesis ofnumerous polycyclic compounds, and cooperative catalyst like copper complex have beenemployed to enhance the reaction efficiency and selectivity. However, syntheticmethodologies employing homogeneous cooperative palladium and iron catalysts are fairlyrare, even though iron catalysis is being exhaustively investigated. Herein, we wish to reportsome novel discovery concerning C-C bond activation and C-H bond activation of alkynonesvia cooperative PdCl₂/FeCl₂-catalyzed cascade cyclization reaction. Further more，we can getthree different complicated compounds respectively in one pot.In this paper, we mainly studied C-C bond activation, C-H bond activation of alkynonesand discovered a PdCl₂/FeCl₂dual-metal catalyst system. Through adjusting and controlingthe solvent, the quantity of co-catalyst and reaction atmosphere we can get the C-C bondactivation and C-H bond activation products respectively. And get three different complicatedcompounds in one pot.The innovation of this paper are that we developed a PdCl₂/FeCl₂catalyst system whichcan not only catalyst C-C bond activation of alkynones but also the C-H bond activation; Thereaction condition is mild, easy to operate. The high regioselectivity and tolerance for a range of functional groups made this protocol very attractiveness. We can get C-C bond activationproduct or C-H bond activation product through controlling the reaction solvent, the quantityof co-catalyst and reaction atmosphere. And we can get three different complicatedcompounds in one pot in this PdCl₂/FeCl₂catalyst system.