Presentation on theme: "Iron-catalyzed Cross Coupling reactions: From Rust to a Rising Star"— Presentation transcript:
1 Iron-catalyzed Cross Coupling reactions: From Rust to a Rising Star Weijun Liu
2 Transition 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.
3 Iron: 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
4 Content: Early Examples 2. Alkenyl Derivatives as Substrates 3. Aryl Derivatives as Substrates4. Alkyl Derivatives as Substrates5. O, N, S-Arylation6. Oxidative Cross-coupling
5 Early ExamplesJ. Kochi, J. Am. Chem. Soc. 1971, 93, 1487
34 X = N, O, SLi, Z.-P. Angew. Chem., Int. Ed. 2008, 47, 7497
35 Summary1. 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.