Ruthenium Porphyrin Catalyzed Intramolecular Carbenoid C−H Insertion. Stereoselective Synthesis of Cis-Disubstituted Oxygen and Nitrogen Heterocycles

Cheung, Wai-Hung; Zheng, Shilong; Yu, Wing‐Yiu; Zhou, Guangyuan; Che, Chi‐Ming

doi:10.1021/ol034806q

Cited by 125 publications

(55 citation statements)

References 20 publications

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“…Aryl tosylhydrazones are converted into b-lactams in good yields and remarkable cis selectivity (up to 99%) using a ruthenium porphyrin-catalyzed stereoselective intramolecular carbenoid CÀH insertion [70]. …”

Section: Hydroxamate Cyclizationmentioning

confidence: 99%

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The Chemistry of 2‐Azetidinones (β‐Lactams)

Alcaide¹,

Almendros²,

Luna³

2011

Modern Heterocyclic Chemistry

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The large number of recent reports on b-lactam chemistry demonstrates the increasing interest in this important class of compounds. Monocyclic b-lactams frequently serve as precursors for the synthesis of classical bicyclic b-lactam antibiotics. The cyclic 2-azetidinone skeleton has been extensively used as a template on which to build the heterocyclic structure fused to the four-membered ring, using the chirality and functionalization of the b-lactam nucleus as a stereocontrolling element. The discovery of nonclassical b-lactam antibiotics, such as monobactams and nocardicins, coupled with ever-growing new applications such as enzyme inhibition has triggered a renewed interest in the building of new monocyclic b-lactam derivatives. Besides the utility of b-lactams as biologically active agents, they are used as intermediates in a-and b-amino acid synthesis, as well as building blocks for alkaloids, heterocycles, taxoids and other types of compounds of biological and medicinal interest. Physicochemical Data Computational ChemistryTheoretical studies show that b-lactams are weaker bases, in the gas phase, than acyclic amides [1]. The attenuation of basicity upon cyclization is stronger than that found for cyclic ketones of similar size due to the existence of a negative hyperconjugation effect that is present in b-lactams but not in cyclic ketones. Ab initio calculations indicate that both b-lactams and acyclic amides are oxygen bases, but the gap between the oxygen and nitrogen intrinsic basicities is much smaller in the former due to the aforementioned cyclization effects. This decrease of the oxygen Modern Heterocyclic Chemistry, First Edition. Edited

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Section: Hydroxamate Cyclizationmentioning

confidence: 99%

“…The antibacterial effect of b-lactam antibiotics such as penicillins (70) and cephalosporins (71) is due to their capacity to disrupt bacterial cell wall biosynthesis [181]. This is achieved by the antibiotics acting as inhibitors of penicillin binding proteins (PBPs), which are membrane bound serine peptidases.…”

Section: Introductionmentioning

confidence: 99%

The Chemistry of 2‐Azetidinones (β‐Lactams)

Alcaide¹,

Almendros²,

Luna³

2011

Modern Heterocyclic Chemistry

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“…A number of groups have successfully synthesized dihydrobenzofurans (51) in high enantioselectivity, but the right combination of catalyst and substrate needs to be used [64][65][66]. In all cases, ortho-substituted benzene rings are the precursors for the C-H insertion events.…”

Section: Synthesis Of Dihydrobenzofurans: Catalyst and Substrate Compmentioning

confidence: 99%

Functionalization of Carbon–Hydrogen Bonds Through Transition Metal Carbenoid Insertion

Davies

Dick

2009

C-H Activation

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The functionalization of carbon-hydrogen bonds through transition metal carbenoid insertion is becoming a powerful method for the construction of new carbon-carbon bonds in organic synthesis. This chapter will highlight recent developments in this field, while placing it within its historical context. Intramolecular carbenoid C-H insertion will be covered first, focusing on formation of three-and six-membered rings, as well as the use of nontraditional substrates. Additionally, the most recent progress in asymmetric catalysis will be discussed. The bulk of the chapter will concentrate on intermolecular transformations, emphasizing both the effect of substrate structure and the influence of carbene substituent electronics on the regioselectivity of the reactions. Vinyldiazoacetates will be covered as a distinct class of carbenoid precursors, as they have been shown to initiate a variety of unique transformations, such as the combined C-H activation/Cope rearrangement. Finally, the synthetic utility of carbenoid C-H insertion reactions, both intra-and intermolecular, will be displayed through their use in the total syntheses of a number of natural products and pharmaceuticals.

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“…1,2 Although several general methods for their synthesis have been developed, [3][4][5][6][7][8][9][10][11][12] they often suffer from the use of expensive transition-metal catalysts or toxic reagents and multistep preparation of the starting materials. Hence, efficient and general methods for the synthesis of both dihydrobenzofurans and dihydroindoles from easily accessible starting materials using inexpensive and low-toxicity catalysts are still needed.…”

Section: Introductionmentioning

confidence: 99%