Presentation on theme: "Iron-catalyzed Cross Coupling reactions: From Rust to a Rising Star"— Presentation transcript:
1Iron-catalyzed Cross Coupling reactions: From Rust to a Rising Star Weijun Liu
2Transition metal catalyzed cross couplings have seen incredible advances and applications, have wide scope and compatibility. But…..typically use palladium and nickel which are generallytoxic and expensive.Expensive and/or sensitive ancillary ligands are required.Alkyl iodides, bromides and triflates are best.With special ligands alkyl chlorides may be used.
3Iron: A More Practical Alternative Iron is one of the most abundant metals on earth. (5.6% of earth’s crust. 4th most abundant element after oxygen, silicon, and aluminum. Nickel is %, palladium is %, gold is % of Earth’s continental crust.)2. Cheap•PdCl2: $4005/150g $26.70/g•NiCl2: $98.40/250g $0.39/g•FeCl3: $30.40/1kg $0.03/g3. nontoxic•Prevalent in biological systems
4Content: Early Examples 2. Alkenyl Derivatives as Substrates 3. Aryl Derivatives as Substrates4. Alkyl Derivatives as Substrates5. O, N, S-Arylation6. Oxidative Cross-coupling
5Early ExamplesJ. Kochi, J. Am. Chem. Soc. 1971, 93, 1487
34X = N, O, SLi, Z.-P. Angew. Chem., Int. Ed. 2008, 47, 7497
35Summary1. Iron catalysts activate alkenyl, aryl, and alkyl derivatives.2. Iron catalysts activate aryl chlorides, triflates and tosylates under ligand free conditions.3. Iron-catalyzed cross-coupling shows excellent functional group tolerance.4. Iron-catalyzed cross-coupling needs only short reaction (typically 5-30 min) time and are performed at low temperatures (typically -20 oC to 0 oC).6. Iron salts has been successfully applied in the C-H bond activation and oxidative coupling reactionsBut the iron-catalyzed cross coupling is not nearly as mature as its palladium and nickel counterparts. And the reaction mechanisms are needed to be proved.