Dehydrogenation and Related Reactions Catalyzed by Iridium Pincer Complexes Zehua Yang Apr.23, 2011
Contents Introduction Dehydrogenation of Alkanes Dehydrogenation Involving Heteroatom-Hydrogen Bonds Related Reactions Conclusions and Outlook 2
1. Introduction Variable pincer ligand parameters for control over steric and electronic properties Jongwook C.; Goldman, A. S. Chem. Rev. 2011, 111, 1761. 3
Alan S. Goldman 1980, B.A. degree, Columbia College. 1985, Ph.D. degree, Columbia University. supervisor Prof. David Tyler. 1985-1987, Postdoctoral Fellow, University of Chicago 1987, The State University of New Jersey. Research interests: Catalytic functionalization of C-H bonds. Pincer catalysts for alkane dehydrogenation. Alkane Metathesis. Hydrocarbylation of olefins. 4
2. Dehydrogenation of Alkanes 2.1 Alkane Dehydrogenation Catalyzed by Non-Pincer-Ligated Transition-Metal Complexes Crabtree, R. H.; Mihelcic, J. M.; Quirk, J. M. J. Am. Chem. Soc. 1979, 101, 7738. Maguire, J. A.; Petrillo, A.; Goldman, A. S. J. Am. Chem. Soc. 1992, 114, 9492. 5
2.2 Dehydrogenation of Alkanes by Pincer Iridium Complexes Gupta, M. Kaska, W. C.; Jensen, C. M. Chem. Commun. 1996, 2083. 6
Acceptorless Dehydrogenatgion by Pincer Iridium Complexes Xu, W, Goldman, A. S. Chem. Commun. 1997, 2273. 7
Proposed Mechanism of n-alkane/tbe Transfer Dehydrogenation by 3-H 2 Renkema, K. B.; Kissin, Y. V.; Goldman, A. S. J. Am. Chem. Soc. 2003, 125, 7770. 8
Dehydrogenation of the terminal position of n-alkanes Liu, F. Jensen, C. M.; Goldman, A. S. J. Am. Chem. Soc. 1999, 121, 4086. 9
Possible Pathways for the Ir-Catalyzed Isomerization of Terminal to Internal Olefins Biswas, S.; Goldman, A.; Huang, Z.;Krogh-Jespersen, K. Abstracts of Papers, 239th ACS National Meeting, San Francisco, CA, March 21-25, 2010; 10
Various iridium pincer complexes used for alkane dehydrogenation Jongwook Choi, Alan S. Goldman, Chem. Rev. 2011, 111, 1761. 11
2.3 Dehydroaromatization of n-alkanes Yield: 44% for 17 Ahuja, R.; Brookhart, M.; Goldman, A. S. Nature Chem. 2011, 3, 167-176. 12
86% for 17 Dehydroaromatization of n-octane Ahuja, R.; Brookhart, M.; Goldman, A. S. Nature Chem. 2011, 3, 167-176. 13
Proposed Mechanism for Dehydroaromatization of n-octane Ahuja, R.; Brookhart, M.; Goldman, A. S. Nature Chem. 2011, 3, 167-176. 14
Synthesis of Higher Alkylarenes by Dehydroaromatization Ahuja, R.; Brookhart, M.; Goldman, A. S. Nature Chem. 2011, 3, 167-176. 15
2.4 Dehydrogenation of Alkyl Groups of Functionalized Substrates Gupta, M.; Kaska, W. C.; Jensen, C. M. Chem. Commun. 1997, 461. Zhang, X.; Fried, A.; Knapp, S.; Goldman, A. S. Chem.Commun. 2003, 2060. 16
synthesis of Á, Â-unsaturated ketones via the dehydrogenation of ketones Zhang, X, Emye, T. J. Goldman, A. S. Inorg. Chim. Acta, 2011, 369, 253-259. 17
Dehydrogenation of acyclic ethers Choi, J, Choliy, Y, Zhang, X, Goldman, A. S. J. Am. Chem. Soc. 2009, 131, 15627. 18
Deydrogenation of saturated polyolefins Ray, A.; Goldman, A. S.; Cherian, A. E.; Coates, G. W. J. Mol. Catal. A 2006, 256, 200. 19
Dehydrogenation during the metalation of sp 3 -hybridized carbon-supported pincer Arunachalampillai, A.; Olsson, D.; Wendt, O. F. Dalton Trans. 2009, 8626. 20
3. Dehydrogenation Involving Heteroatom-Hydrogen Bonds 3.1 Dehydrogenation of Amine-Boranes Denney, M. C.; Heinekey, D. M.; Goldberg, K. I. J. Am. Chem. Soc. 2006, 128, 12048. Dietrich, B. L.; Goldberg, K. I.; Linehan, J. C. Inorg. Chem. 2008, 47, 8583. 21
Proposed Mechanism of Ammonia-Borane Dehydrogenation by 9a-H 2 Sloan, M. ELloyd-Jones, G. C.; Manners, I. J. Am. Chem. Soc. 2010, 132, 3831. 22
3.2. Dehydrogenation of C-N and C-O Linkages and Related Reactions Morales-Morales, D.; Jensen, C. M. Can. J. Chem. 2001, 79, 823. 23
Dehydrogenation of Amines Gu, X.-Q.; Morales-Morales, D.; Jensen, C. M. J. Mol. Catal. A 2002, 189, 119. 24
C-C Bond Cleavage in Aminoethyl Groups in Secondary Amines Zhang, X.; Emge, T. J.; Ghosh, R.; Goldman, A. S. J. Am. Chem. Soc. 2005, 127, 8250. 25
Proposed Mechanism for the Dehydrogenation of Primary Amines to Nitriles by 9a Bernskoetter, W. H.; Brookhart, M. Organometallics 2008, 27,2036. 26
4. Related Reactions 4.1. Hydrogenation of C=O Bonds Hydrogenation of Ketones by 32 Azerraf, C.; Gelman, D. Organometallics 2009, 28, 6578 27
Mechanism for CO 2 Hydrogenation by 42b Ben-Ari, E,; Shimon, L. J. W.; Milstein, D. J. Am.Chem. Soc. 2006, 128, 15390. 28
4.2. Formation of Carbene Complexes via Á, Á-Dehydrogenation and Reactions with Heterocumulenes Whited, M. T.; Grubbs, R. H. J. Am. Chem. Soc. 2008, 130,16476. 29
5. Conclusions and Outlook Pincer ligands offer high thermal stability and great control of the steric and electronic properties of metal centers. Pincer iridium complexes have found utility in numerous but it is in the dehydrogenation of alkyl groups where they have dominated the field. The factors that make iridium pincer complexes so effective for alkane dehydrogenation may also be applicable to seemingly unrelated reactions. 30
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