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Iron-catalyzed Cross Coupling reactions: From Rust to a Rising Star Weijun Liu.

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Presentation on theme: "Iron-catalyzed Cross Coupling reactions: From Rust to a Rising Star Weijun Liu."— 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 generally toxic 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 1.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/g 3. nontoxic Prevalent in biological systems

4 Content: 1.Early Examples 2. Alkenyl Derivatives as Substrates 3. Aryl Derivatives as Substrates 4. Alkyl Derivatives as Substrates 5. O, N, S-Arylation 6. Oxidative Cross-coupling

5 1.Early Examples J. Kochi, J. Am. Chem. Soc. 1971, 93, 1487

6 Kochi, J. J. Org. Chem. 1976, 41, 502

7 NMP as cosolvent Cahiez, G. Synthesis 1998, Alkenyl Derivatives as Substrates

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9 Cahiez, G. Synthesis 1998, 1199

10 Cahiez, G.; Knochel, P. Synlett 2001, %

11 3. Aryl Derivatives as Substrates Furster, A. Angew. Chem., Int. Ed. 2002, 41, 609

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14 Proposed Formal Catalytic Cycle

15 4. Alkyl Derivatives as Substrates Furster, A. Angew. Chem., Int. Ed. 2004, 43, 3955

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18 Only tertiary halides and alky chlorides were found be inert.

19 Nakamura, E. J. Am. Chem. Soc. 2004, 126, 3686

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22 Hayashi, T. Org. Lett. 2004, 6, 1279

23 Cossy, J. Angew. Chem., Int. Ed. 2007, 46, 6521

24 51% Chai, C.L.L. Adv. Synth., Catal. 2007, 349, 1015

25 5. O, N, S-Arylation Bolm, C. Angew. Chem., Int. Ed. 2007, 46, 8862

26 Bolm, C. Angew. Chem., Int. Ed. 2007, 47, 586 Bolm, C. Angew. Chem., Int. Ed. 2008, 47, 2880

27 6. Oxidative Cross-coupling Iron-Catalyzed Homo-Coupling FeI/FeIII or Fe0/FeII Cahiez, G. Org. Lett. 2005, 7, 1943 Fe-II/Fe0

28 Cahiez, G. J. Am. Chem. Soc. 2007, 129, 13788

29 Oxidative Heterocoupling Cahiez, G. Angew. Chem., Int. Ed. 2009, 43, ASAP

30 Iron-Catalyzed Direct Arylation through Directed C-H Bond Activation

31 Nakamura, E. J. Am. Chem. Soc. 2008, 130, 5858

32 Iron-Catalyzed Chemoselective ortho Arylation of Aryl Imines by Directed C-H Bond Activation Nakamura, E. Angew. Chem., Int. Ed. 2009, 48, ASAP

33 Li, Z.-P.; Li, C.-J. Angew. Chem., Int. Ed. 2007, 46, 6505

34 X = N, O, S Li, Z.-P. Angew. Chem., Int. Ed. 2008, 47, 7497

35 Summary 1. 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 reactions But 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.


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