C-H Bond Activation and Catalytic Functionalization II

Table of Contents

1. Frontmatter

2. Iron-Catalyzed C–H Bond Activation

   Laurean Ilies, Eiichi Nakamura

   Abstract

   Iron-catalyzed C–H bond activation followed by C–C bond formation has received much attention in recent years, motivated by the environmental and economical merits of iron, as well as the scientific challenge in controlling and understanding the reactivity of iron species. This review describes the utilization of iron as a catalyst for directed C–H bond activation, followed by C–C bond formation. Catalytic activation of C(sp²)-H and C(sp³-H) bonds, followed by oxidative reaction with nucleophiles, or reaction with electrophiles is described. Reactions of substrates possessing a directing group are mainly discussed, but other substrates are also presented. Carbon–heteroatom bond formation is also briefly discussed.

3. Nickel-Catalyzed C–H Bond Functionalization Utilizing an N,N′-Bidentate Directing Group

   Naoto Chatani

   Abstract

   This review discusses the use of nickel catalysts and N,N′-bidentate directing groups, such as 2-pyridinylmethylamine, 8-aminoquinoline, and derivatives thereof, which constitute a powerful combination for the chelation-assisted functionalization of C–H bonds.

4. Copper-Mediated Intermolecular C–H/C–H and C–H/N–H Couplings via Aromatic C–H Cleavage

   Koji Hirano, Masahiro Miura

   Abstract

   Copper salts and complexes have recently received significant attention as less expensive and abundant alternatives to some noble transition metal catalysts such as palladium, rhodium, and ruthenium, in the research field of C–H activation. They not only replace the above precious metal catalysts in the known C–H transformations but also mediate unique, otherwise challenging, cross-coupling reactions involving C–H bond cleavage. This chapter mainly focuses on recent advances in the copper-mediated or copper-catalyzed intermolecular C–H/C–H and C–H/N–H aromatic couplings. Seminal mechanistic studies on the copper-mediated C–H functionalization are also discussed.

5. The Effects of Ancillary Ligands on Metal–Carbon Bond Strengths as Determined by C–H Activation

   William D. Jones

   Abstract

   The activation of C–H bonds by oxidative addition in about 30 different substrates has been examined with three closely related metal species, [Tp′RhL], where L = CNneopentyl, PMe₃, and P(OMe)₃. Kinetic studies of the reductive elimination of R–H provided data to ascertain the relative metal–carbon bond strengths for a wide range of compounds. Trends in these bond strengths reveal that there are two classes of C–H substrates: parent hydrocarbons and substituted methanes. DFT calculations are used to support the observed trends, and some generalizations are made by comparison to other metal systems.

6. Catalytic C–H Bond Functionalization of Cyclopropane Derivatives

   Daniela Sustac Roman, André B. Charette

   Abstract

   The present work describes a comprehensive review of the functionalization of cyclopropyl C–H bonds via transition-metal catalysis. Compared to the enormous number of publications related to direct sp² and sp³ bond transformations in the last two decades, the first full account of direct cyclopropyl C(sp³)–H bond functionalization was only disclosed in 2011. Both intra- and intermolecular transformations are detailed in the review, including asymmetric reactions. In addition, mechanistic aspects of various Pd-catalyzed cyclopropane functionalizations are discussed.

7. Silver-Mediated Direct sp3 C–H Bond Functionalization

   Taigang Zhou, Zhang-Jie Shi

   Abstract

   Direct sp³ C–H bond functionalization is an efficient, straightforward, and powerful method to construct new C–X (X=C, N, F, S) bonds from nonfunctionalized aliphatic motif of organic molecules, which has been used in late-stage modification of complex molecules. In this chapter, the recent developments of silver-mediated direct sp³ C–H functionalizations are reviewed, categorized by C–C bond formation (C–H insertion), C–N bond formation (intramolecular and intermolecular amination/amidation), C–F bond formation, and C–S bond formation.

8. Applications of Catalytic Organometallic C(sp3)–H Bond Functionalization

   David Dailler, Grégory Danoun, Olivier Baudoin

   Abstract

   The transition-metal-catalyzed activation of C(sp³)–H bonds has emerged as powerful strategy to create bonds and introduce functional groups in a direct fashion. This review focuses on recent applications of C(sp³)–H bond functionalization strategies to the synthesis of biologically active and natural compounds.

9. New Concept of C–H and C–C Bond Activation via Surface Organometallic Chemistry

   Manoja K. Samantaray, Raju Dey, Santosh Kavitake, Jean-Marie Basset

   Abstract

   In this chapter we describe the recent applications of well-defined oxide-supported metal alkyls/alkylidenes/alkylidynes and hydrides of group IV, V, and VI transition metals in the field of C–H and C–C bond activation. The activation of ubiquitous C–H and C–C bonds of paraffin is a long-standing challenge because of intrinsic low reactivity. There are many concepts derived from surface organometallic chemistry (SOMC): surface organometallic fragments are always intermediates in heterogeneous catalysis. The study of their synthesis and reactivity is a way to rationalize mechanism of heterogeneous catalysis and to achieve structure activity relationship. By surface organometallic chemistry one can enter any catalytic center by a reaction intermediate leading in fine to single site catalysts. With surface organometallic chemistry one can coordinate to the metal which can play a role in different elementary steps leading for example to C–H activation and Olefin metathesis. Because of the development of SOMC there is a lot of space for the improvement of homogeneous catalysis. After the 1997 discovery of alkane metathesis using silica-supported tantalum hydride by Basset et al. at low temperature (150^oC) the focus in this area was shifted to the discovery of more and more challenging surface complexes active in the application of C–H and C–C bond activation. Here we describe the evolution of well-defined metathesis catalyst with time as well as the effect of support on catalysis. We also describe here which metal–ligand combinations are responsible for a variety of C–H and C–C bond activation.

10. Transfer Dehydrogenations of Alkanes and Related Reactions Using Iridium Pincer Complexes

    David Bézier, 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.

11. Backmatter