Asymmetric Cyclopropanation and Aziridination Reactions

Charette, André B.; Lebel, H.; Roy, M. N.

doi:10.1002/9783527664573.ch8

Cited by 11 publications

(5 citation statements)

References 159 publications

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“…Polysubstituted cyclopropanes are useful intermediates in organic synthesis that have attracted a lot of interest due mainly to their easy ring opening under acidic, basic, or free-radical conditions . Cyclopropanes are readily available in enantiopure form using now well-established organometallic and organocatalyzed processes . Recent progress in the stereocontrolled synthesis of cyclopropanes also includes the functionalization of substituted cyclopropenes .…”

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confidence: 99%

Free-Radical Carbocyanation of Cyclopropenes: Stereocontrolled Access to All-Carbon Quaternary Stereocenters in Acyclic Systems

2016

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confidence: 99%

Free-Radical Carbocyanation of Cyclopropenes: Stereocontrolled Access to All-Carbon Quaternary Stereocenters in Acyclic Systems

2016

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“…Pd catalysts have indeed been found to be active but poorly enantioselective for asymmetric cyclopropanation, probably because of decomplexation of the ligand during the reaction . Moderate levels of enantioinduction have been achieved with chiral Cu–diamino complexes, although the substrate scope is very limited . However, many other examples showing higher enantioselectivities were disclosed with diazoalkanes bearing electron-withdrawing groups, such as α-diazo esters. ,, …”

Section: Resultsmentioning

confidence: 99%

“…Moderate levels of enantioinduction have been achieved with chiral Cu–diamino complexes, although the substrate scope is very limited . However, many other examples showing higher enantioselectivities were disclosed with diazoalkanes bearing electron-withdrawing groups, such as α-diazo esters. ,, …”

Section: Resultsmentioning

confidence: 99%

Scalable Synthesis of β-Lactamase Inhibitor QPX7728 by Sequential Nickel-Catalyzed Boron Insertion into a Benzofuran Substrate and Enantioselective Cyclopropanation of the Resulting Vinylboronate

Boyer

González-de-Castro²,

Dielemans³

et al. 2021

Org. Process Res. Dev.

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We report the scalable, high-yielding, and highly selective synthesis of the β-lactamase inhibitor QPX7728 featuring two key synthetic steps: nickel-catalyzed boron insertion of benzofuran 1 followed by enantioselective cyclopropanation of the resulting cyclic vinylboronate 2. The identification of the key reagents (catalyst and chiral auxiliary) for both steps relied on the use of high-throughput experimentation. Further optimization allowed for the cost-effective and scalable production of QPX7728.

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“…Copper-based catalysts are particularly attractive due to their high efficiency in asymmetric cyclopropanation reactions [7] and their relatively low cost in comparison with other metal catalysts. In order to gain better understanding of the stereoselectivity governing factors, and thereby upgrade the ability to design more efficient catalytic systems, the mechanism of the copper-catalyzed cyclopropanation reaction of olefins with diazo compounds has been experimentally [6] and theoretically [8] studied in recent years, and the pathway for the global catalytic cycle is now well established.…”

Section: Introductionmentioning

confidence: 99%

Copper-catalyzed cyclopropanation reaction of but-2-ene

et al. 2018

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The mechanism of the copper(I)-catalyzed cyclopropanation reaction for methyl diazoacetate with both (Z)- and (E)-but-2-ene stereoisomers has been studied using the 6-311++G(d,p) basis set by means of M06-2X and O3LYP functionals. According to both methods, the rate-limiting step is the formation of a copper-carbene intermediate, formed by association between methyl diazoacetate and bis(acetonitrile)-copper(I) ion with the concomitant extrusion of dinitrogen. Cis/trans diastereoselectivity for the cyclopropanation reaction of a 1,2-disubstituted alkene ((Z)-but-2-ene) has been theoretically studied for the first time through the proper location of transition states on the potential-energy surface with the O3LYP method, since no transition structures could be found with the M06-2X functional due to the extreme flatness of the potential-energy surface. The calculated stereoselectivities involving two acetonitrile ligands or one dichloromethane molecule show qualitative agreement with experimental data. This study allows attributing the origin of the selectivity to steric interactions between the ligands of the catalyst system and the olefin substituents. The comparison between the corresponding activation barriers for the direct insertion step shows a higher reactivity for the Z stereoisomer of but-2-ene, consistently with the larger reactant destabilization through steric interactions.

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Asymmetric Cyclopropanation and Aziridination Reactions

Cited by 11 publications

References 159 publications

Free-Radical Carbocyanation of Cyclopropenes: Stereocontrolled Access to All-Carbon Quaternary Stereocenters in Acyclic Systems

Free-Radical Carbocyanation of Cyclopropenes: Stereocontrolled Access to All-Carbon Quaternary Stereocenters in Acyclic Systems

Scalable Synthesis of β-Lactamase Inhibitor QPX7728 by Sequential Nickel-Catalyzed Boron Insertion into a Benzofuran Substrate and Enantioselective Cyclopropanation of the Resulting Vinylboronate

Copper-catalyzed cyclopropanation reaction of but-2-ene

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