C–H Transformation at Functionalized Alkanes

Murahashi, Shun‐Ichi; Yamamoto, Yoshinori; Bajracharya, Gan B.; Nicolau, Claudio Palomo; Oiarbide, Mikel; Hamashima, Yoshitaka; Sodeoka, Mikiko; Córdova, Armando; Snider, Barry B.; Yoshimitsu, Takehiko; Minisci, Francesco; Porta, Ombretta; Stoltz, Brian M.; Ebner, D. C.; Ganesan, A.; Kaskel, Stefan; Varela, Jesús A.; Dyker, Gerald; Christiansen, Andrea; Börner, Armin; Matsubara, Seijiro; Frison, Jean Cédric; Legros, Julien; Bolm, Carsten; He, Minsheng; Lei, Aiwen; Zhang, Xumu; Sezen, Bengü; Sameš, Dalibor

doi:10.1002/9783527619450.ch8

Cited by 5 publications

(5 citation statements)

References 711 publications

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“…Aryl chloride 86 demonstrates the preference for arylation at a methyl C−H bond over arylation at typically more reactive benzylic C(sp 3 )−H and aryl C(sp 2 )−H bonds (entry 7). , Indeed, indanone 87a was isolated as the major product in 65% yield, together with the direct arylation product 87b in 32% yield, while no product resulting from arylation at the benzylic C(sp 3 )−H bond was detected. These results (Table , entries 4, 5, and 7), combined with those for amine 64 (Table , entry 8) as well as with previous data, appear to indicate that steric interactions contribute significantly to reaction site selectivity, overriding electronic influences at the methylene C(sp 3 )−H bond known to promote reactivity, such as the α heteroatom effect in 64 and acidity in 80 , 82 , and 86 .…”

Section: Resultssupporting

confidence: 80%

Intramolecular Palladium-Catalyzed Alkane C−H Arylation from Aryl Chlorides

et al. 2010

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The first examples of efficient and general palladium-catalyzed intramolecular C(sp(3))-H arylation of (hetero)aryl chlorides, giving rise to a variety of valuable cyclobutarenes, indanes, indolines, dihydrobenzofurans, and indanones, are described. The use of aryl and heteroaryl chlorides significantly improves the scope of C(sp(3))-H arylation by facilitating the preparation of reaction substrates. Careful optimization studies have shown that the palladium ligand and the base/solvent combination are crucial to obtaining the desired class of product in high yields. Overall, three sets of reaction conditions employing P(t)Bu(3), PCyp(3), or PCy(3) as the palladium ligand and K(2)CO(3)/DMF or Cs(2)CO(3)/pivalic acid/mesitylene as the base/solvent combination allowed five different classes of products to be accessed using this methodology. In total, more than 40 examples of C-H arylation have been performed successfully. When several types of C(sp(3))-H bond were present in the substrate, the arylation was found to occur regioselectively at primary C-H bonds vs secondary or tertiary positions. In addition, in the presence of several primary C-H bonds, selectivity trends correlate with the size of the palladacyclic intermediate, with five-membered rings being favored over six- and seven-membered rings. Regio- and diastereoselectivity issues were studied computationally in the prototypal case of indane formation. DFT(B3PW91) calculations demonstrated that C-H activation is the rate-determining step and that the creation of a C-H agostic interaction, increasing the acidity of a geminal C-H bond, is a critical factor for the regiochemistry control.

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Section: Resultssupporting

confidence: 80%

Intramolecular Palladium-Catalyzed Alkane C−H Arylation from Aryl Chlorides

et al. 2010

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“…As it typical example, (4R)-4-CO,H (rut-butyldimethylsiloxy)-I-pyrroline N-oxide(38), which is a versatile intermediate for the synthesis of optically active pyrrolidines, can be prepared simply in 70 % yield by treating a solution of tmns-4-(tert-butylsiloxy)-~-proline (37) in dichloromethane with hydrogen peroxide in the presence of Na,WO, Schcnie 3 Tlingarate-catalyled oxidation of secondary amines REVIEWS catalyst and tetraethylammonium chloride. [291 On the other hand, (3R)-3-(terr-butyldimethylsiloxy)-l-pyrroline…”

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Synthetic Aspects of Metal‐Catalyzed Oxidations of Amines and Related Reactions

Murahashi

1995

Angew. Chem. Int. Ed. Engl.

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224

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The metabolism of amines is governed by a variety of enzymes such as amine oxidase, flavoenzyme, and cytochrome P‐450. A wide variety of compounds are produced such as ammonia and alkaloids in selective and clean oxidation reactions that proceed under mild reaction conditions. Simulation of the functions of these enzymes with simple transition metal complex catalysts may lead to the discovery of biomimetic, catalytic oxidations of amines and related compounds. Indeed, metal complex catalyzed oxidations have been found to proceed with high efficiency. The first section of this review discusses the dehydrogenative oxidations of amines with transition metal catalysts by transition metal catalysts that simulate amine oxidase. The second section highlights the catalytic oxidation of secondary amines to nitrones by simulation of flavoenzymes. The third section describes the simulation of the function of cytochrome P‐450 with lowvalent ruthenium complexes and peroxides. Biomimetic ruthenium‐catalyzed oxidations of tertiary amines, secondary amines, and other substrates such as amides, β‐lactams, nitriles, alcohols, alkenes, ketones, and even nonactivated hydrocarbons can be performed selectively under mild conditions. These three general approaches provide highly useful strategies for synthesis of fine chemicals and biologically active compounds such as alkaloids, amino acids, and β‐lactams.

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“…Service designers use the 'Double Diamond' model. The first diamond deals with understanding the problem, and the second diamond represents the creation of a solution [40]. As shown in Figure 1, the service design process is divided into four phases: Discover phase, Define phase, Develop phase and Deliver phase.…”

Section: Service Designmentioning

confidence: 99%

Integrated Real-Time Information System for Public Commuting: Perspectives of Stakeholders in South Africa

Hlophe,

Afolayan,

Daramola

2024

IJTDI

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Decision-making while commuting in big cities is still challenging for many citizens in developing countries. The implementation of diverse transportation modes operating in silos combined with the inaccessibility of real-time travel information prevents commuters from these countries from making informed travel decisions. Commuters often have to choose the specific means of transport that will yield the highest value in terms of cost, safety, convenience, and timeliness among alternatives. This paper uses a case study of Cape Town in South Africa to explore stakeholders' perspectives on implementing an integrated real-time information system (IRIS) and the requirements that must be satisfied. We employed a qualitative methodology, utilising semi-structured interviews and codesign sessions as the means of data collection. Four categories of stakeholders associated with transportation, including taxis, trains, Bus Rapid Transit (BRT), and municipal buses, within the context of South Africa, participated in the study. The findings reveal that the commuters and the public transport operators agreed that challenges around socio-traffic incidents, infrastructure development, lack of technology resources and lack of real-time travel information are major concerns that must be addressed for successful IRIS implementation. Functional features, change management, data privacy, system integration and information sharing were the main priorities on the list of requirements. The study represents a first attempt at understanding the requirements of an IRIS from the stakeholders' perspective in the context of South Africa. It extends the discussion on using IRIS to support transportation in developing countries, which has received limited attention thus far in the literature. The study is relevant for developing futuristic policies, advanced infrastructure, and optimised service delivery in developing countries because it provides a good foundation for understanding the critical requirements for the design and development of IRIS.

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C–H Transformation at Functionalized Alkanes

Cited by 5 publications

References 711 publications

Intramolecular Palladium-Catalyzed Alkane C−H Arylation from Aryl Chlorides

Intramolecular Palladium-Catalyzed Alkane C−H Arylation from Aryl Chlorides

Synthetic Aspects of Metal‐Catalyzed Oxidations of Amines and Related Reactions

Integrated Real-Time Information System for Public Commuting: Perspectives of Stakeholders in South Africa

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