Switching the site-selectivity of C–H activation in aryl sulfonamides containing strongly coordinating N-heterocycles

Dong, Yunhui; Zhang, Xuepeng; Chen, Jiajing; Zou, Wenxing; Lin, Songwen; Xu, Heng

doi:10.1039/c9sc03691a

Cited by 29 publications

(17 citation statements)

References 93 publications

(78 reference statements)

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“…The stereochemistry of 7 and 7′ is assigned on the basis of 1-D NOESY and by comparing 1 H chemical shift values of 7 and 7′ with dibenzyl 2-(1-methylpyrrolidin-2-ylidene)malonate ( 8 ) (see the Supporting Information for details). Compound 8 was prepared by the coupling reaction 39 of dibenzyl 2-diazomalonate ( 9 ) 40 and 1-methylpyrrolidine-2-thione ( 10 ). 41 The equilibrium overwhelmingly favors 7 ( 7 : 7′ 17.6:1).…”

Section: Resultsmentioning

confidence: 99%

Application of NMR Spectroscopy for the Detection of Equilibrating E–Z Diastereomers

et al. 2020

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Conjugation can lower the energy barrier for unsaturated C–C bond rotations, resulting in a mixture of equilibrating diastereomers at room temperature. Therefore, methods claiming diastereoselective synthesis of conjugated double bonds often require proof that the observed diastereomeric ratio is not because of the diastereomeric equilibration of the product. Variable-temperature (VT) NMR experiments are commonly used to distinguish between the two possibilities. However, the VT technique requires accessories for the NMR spectrometer and more setup time. Here, we show that the rarely used application of 1-D and 2-D nuclear Overhauser effect spectroscopy experiments for the detection of the equilibrating diastereomers is a convenient alternative to the VT technique.

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Section: Resultsmentioning

confidence: 99%

Application of NMR Spectroscopy for the Detection of Equilibrating E–Z Diastereomers

et al. 2020

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“…Moreover, this switchable site‐selectivity carbenoid functionalization methodology, well‐tolerated in case of diverse strongly coordinating N‐ heterocycles and the proof of the site‐selective methodology‘s mechanism further investigated by experimental studies and DFT calculations (Scheme 28). [40] …”

Section: C−h Alkylation With Carbene Precursorsmentioning

confidence: 99%

Co(III), Rh(III) & Ir(III)‐Catalyzed Direct C−H Alkylation/Alkenylation/Arylation with Carbene Precursors

Nunewar

Kumar

Talakola

et al. 2021

Chemistry An Asian Journal

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Metal carbenes play a pivotal role in transition‐metal‐catalyzed synthetic transfer reactions. The metal carbene is generated either from a diazo compound through facile extrusion of N2 with a metal catalyst or in situ generated from other sources like triazoles, pyriodotriazoles, sulfoxonium ylides and iodonium‐ylide. On the other hand, Co(III), Rh(III) & Ir(III)‐catalyzed C−H functionalizations have been well established as a key synthetic step to enable the construction of various synthetic transformations. Interestingly, in recent years, merging of these two concepts C−H activation and carbene migratory insertion gained much attention, in particular group 9 metal‐catalyzed arene C−H functionalizations with carbene precursors via carbene migratory insertion. In this review, we summarize recent advances in Co(III), Rh(III) & Ir(III)‐catalyzed direct C−H alkylation/alkenylation/arylation with carbene precursors and also discuss key synthetic intermediates within the catalytic cycles.

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“…Recent studies carried out by the same research group [33] described switching of site selectivity of aryl sulphonamides containing strong directing group ( N ‐heterocyclics) ( 32 ) to introduce carbenoid functionalization. Molecules possessing two directing groups afford competitiveness to each other where C−H activation is less likely to occur by a weakly co‐ordinating group than the strongly directing group.…”

Section: The C−c Bond Formationmentioning

confidence: 99%

The Role of Sulphonamides and N‐Sulphonyl Ketimines/Aldimines as Directing Groups in the Field of C−H Activation

Galla

Bora

Shankaraiah

2021

Chemistry An Asian Journal

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Sulphonamides and N‐sulphonyl ketimines/aldimines have turned out to be versatile motifs in the field of synthetic and medicinal chemistry. The field of C−H activation/functionalization flourished remarkably due to their synthetic applicability and directing group plays a remarkable role to achieve regioselectivity in these reactions. The current review summarizes recent tactics by utilizing sulphonamides and N‐sulphonyl ketimines/aldimines as directing groups for C−H activation or functionalization. As a directing group, they also facilitate site selectivity and late‐stage functionalization of drug molecules in order to construct complex scaffolds of therapeutic importance by C−H activation.

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Switching the site-selectivity of C–H activation in aryl sulfonamides containing strongly coordinating N-heterocycles

Abstract: Switching the site-selectivity of C–H activation in aryl sulfonamides containing strongly coordinating N-heterocycles was achieved using a RhIII-catalyst.

Cited by 29 publications

References 93 publications

Application of NMR Spectroscopy for the Detection of Equilibrating E–Z Diastereomers

Application of NMR Spectroscopy for the Detection of Equilibrating E–Z Diastereomers

Co(III), Rh(III) & Ir(III)‐Catalyzed Direct C−H Alkylation/Alkenylation/Arylation with Carbene Precursors

The Role of Sulphonamides and N‐Sulphonyl Ketimines/Aldimines as Directing Groups in the Field of C−H Activation

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