Rhodium(II)‐Catalyzed Oxidative Amination

Espino, Christine G.; Bois, J. Du

doi:10.1002/3527604693.ch17

Cited by 105 publications

(47 citation statements)

References 100 publications

(158 reference statements)

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“…For example, the reaction with trans -4-phenylcyclohexyl- N -tosyloxycarbamate D afforded the ketone and the corresponding primary carbamate in respectively 58% and 15% yields (eqn (7)). The formation of ketones has also been observed in rhodium-catalyzed C–H amination reactions using iminoiodinanes as metal nitrene precursors 92–95. The formation of this by-product was postulated to be the result of an α-C–H insertion reaction producing a strained 4-membered intermediate that decomposes to afford the observed ketone 92.…”

Section: Resultsmentioning

confidence: 87%

“…The formation of ketones has also been observed in rhodium-catalyzed C–H amination reactions using iminoiodinanes as metal nitrene precursors 92–95. The formation of this by-product was postulated to be the result of an α-C–H insertion reaction producing a strained 4-membered intermediate that decomposes to afford the observed ketone 92. No experimental or in silico data are available to support this hypothesis.…”

Section: Resultsmentioning

confidence: 99%

“…Now that the pathway leading to their formation has been established, one can envision that the control of the reaction conditions (more diluted reaction conditions, solvent change) may in some cases minimize the formation of these undesired products. Given that ketones had also been identified as by-products in other rhodium-catalyzed nitrene C–H insertions,92–95 namely with iminoiodinanes, the identified pathway may also be operational in these systems (with the iminoiodinane as the hydride source). Finally, we also established that iodine, through intramolecular coordination of the rhodium nitrene, may in some substrates strongly impede the electrophilic nature of the nitrogen.…”

Section: Discussionmentioning

confidence: 99%

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Rhodium(ii)-catalyzed C–H aminations using N-mesyloxycarbamates: reaction pathway and by-product formation

et al. 2019

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Section: Resultsmentioning

confidence: 87%

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Rhodium(ii)-catalyzed C–H aminations using N-mesyloxycarbamates: reaction pathway and by-product formation

et al. 2019

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“…Numerous reviews have been written about this method for C-H functionalization [11][12][13][14][15][16][17] . Here, however, we highlight another approach, in which a divalent carbon (carbene) 18 or a monovalent nitrogen (nitrene) 19 , coordinated to a metal complex, inserts into a C-H bond 20 . This alternative approach offers many advantages over the metal-induced C-H insertion because the reactions exhibit high turnover numbers and can lead to high levels of selectivity, both in terms of regioselectivity and stereoselectivity (Fig.…”

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confidence: 99%

Catalytic C–H functionalization by metal carbenoid and nitrenoid insertion

Davies

Manning

2008

Nature

2,179

812

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Novel reactions that can selectively functionalize carbon-hydrogen bonds are of intense interest to the chemical community because they offer new strategic approaches for synthesis. A very promising 'carbon-hydrogen functionalization' method involves the insertion of metal carbenes and nitrenes into C-H bonds. This area has experienced considerable growth in the past decade, particularly in the area of enantioselective intermolecular reactions. Here we discuss several facets of these kinds of C-H functionalization reactions and provide a perspective on how this methodology has affected the synthesis of complex natural products and potential pharmaceutical agents.I n 2006, 31 new chemical entities were introduced to the world pharmaceutical market and 2,075 molecules were in phase I or II of clinical development 1 . The majority of these were smallmolecule (relative molecular mass ,1,000) organic compounds 2 . As knowledge about the specific interactions of drugs in vivo increases, often so does the structural complexity of new drug targets. A major obstacle to the development of such drugs is the difficulty associated with synthesizing large quantities in an economical fashion, because complex multi-step syntheses are usually required. In the general media, it is often overlooked that the accessibility of the components required for these new treatments will often govern their eventual success or failure. Likewise, a design element of any pharmaceutical agent is the expectation that the target compounds can be made economically. Therefore, new strategies for synthesis can become enabling technologies, making available new targets and materials that would have been previously out of range. For example, new methodologies such as metal-catalysed crosscoupling 3 and olefin metathesis 4-6 have rapidly become central transformations in the synthesis of new pharmaceutical agents. Selective C-H functionalization is a class of reactions that could lead to a paradigm shift in organic synthesis, relying on selective modification of ubiquitous C-H bonds of organic compounds instead of the standard approach of conducting transformations on pre-existing functional groups. The reactive sites in each type of transformation are very different, as illustrated in Fig. 1.The many opportunities associated with C-H functionalization has made this field an active area of research. Organometallic chemists have focused much attention on developing 'C-H activation' strategies, whereby a highly reactive metal complex inserts into a C-H bond, activating the system for subsequent transformations 7-9 . One of the major challenges associated with this chemistry has been to render it catalytic in the metal complex 10 . A partial solution to this problem has been to use neighbouring functionality to direct less reactive metal complexes to the site for functionalization. Numerous reviews have been written about this method for C-H functionalization [11][12][13][14][15][16][17] . Here, however, we highlight another approach, in which a divalent c...

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“…14 Commercial Rh 2 (OAc) 4 or Rh 2 (oct) 4 proved generally effective for many of these reactions, and that remains true today (catalyst loading typically range from 2–5 mol%, TONs ~20–50). Reactions of carbamates occasionally call for application of the Ikegami/Hashimoto Rh 2 (O 2 CCPh 3 ) 4 , a complex easily generated from Rh 2 (OAc) 4 .…”

Section: Initial Discoveriesmentioning

confidence: 99%