Top Organomet Chem (2016) 56: 189–208
DOI: 10.1007/3418_2015_132
# Springer International Publishing Switzerland 2015
Published online: 29 July 2015
Transfer Dehydrogenations of Alkanes
and Related Reactions Using Iridium Pincer
Complexes
David Be ´zier and Maurice Brookhart
Abstract This chapter covers advances during the past 5 years in using iridium
pincer complexes for transfer dehydrogenations of alkanes as well as related reactions which couple dehydrogenation with other transformations. Several new pincer
complexes are described which have emerged during this period and which have
added not only to the scope of available catalysts but also to the range of substrates
and products generated. Transfer dehydrogenation has been linked with other reactions to produce catalytic systems that carry out alkane metatheses, generate benzene
bearing a long-chain linear alkyl group from ethyl benzene and linear alkanes, couple
alkanes with alkenes, and use transfer dehydrogenation in combination with Diels–
Alder chemistry to produce para-xylene from ethylene as the sole feedstock.
Keywords Alkane functionalization Á C–H activation Á Dehydrogenation Á Iridium
pincer catalysts
Contents
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190
2 Alkane Dehydrogenation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192
3 Applications to the Synthesis of Aromatics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195
4 Applications to the Synthesis of Long-Chain Alkanes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199
5 Dehydrogenation of Functionalized Organic Molecules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201
6 Moving Forward by Using O 2 as Hydrogen Acceptor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
7 Summary and Future Challenges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205
D. Be ´zier and M. Brookhart (*)
Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill,
NC 27599-3290, USA
e-mail: mbrookhart@unc.edu
DOI: 10.1007/3418_2015_132
# Springer International Publishing Switzerland 2015
Published online: 29 July 2015
Transfer Dehydrogenations of Alkanes
and Related Reactions Using Iridium Pincer
Complexes
David Be ´zier and Maurice Brookhart
Abstract This chapter covers advances during the past 5 years in using iridium
pincer complexes for transfer dehydrogenations of alkanes as well as related reactions which couple dehydrogenation with other transformations. Several new pincer
complexes are described which have emerged during this period and which have
added not only to the scope of available catalysts but also to the range of substrates
and products generated. Transfer dehydrogenation has been linked with other reactions to produce catalytic systems that carry out alkane metatheses, generate benzene
bearing a long-chain linear alkyl group from ethyl benzene and linear alkanes, couple
alkanes with alkenes, and use transfer dehydrogenation in combination with Diels–
Alder chemistry to produce para-xylene from ethylene as the sole feedstock.
Keywords Alkane functionalization Á C–H activation Á Dehydrogenation Á Iridium
pincer catalysts
Contents
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190
2 Alkane Dehydrogenation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192
3 Applications to the Synthesis of Aromatics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195
4 Applications to the Synthesis of Long-Chain Alkanes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199
5 Dehydrogenation of Functionalized Organic Molecules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201
6 Moving Forward by Using O 2 as Hydrogen Acceptor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
7 Summary and Future Challenges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205
D. Be ´zier and M. Brookhart (*)
Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill,
NC 27599-3290, USA
e-mail: mbrookhart@unc.edu