Transition-metal-free multinitrogenation of amides by C–C bond cleavage: a new approach to tetrazoles

Li, Lianhua; Niu, Zhi-Jie; Li, Ying-Xiu; Liang, Yong‐Min

doi:10.1039/c8cc06324a

Cited by 24 publications

(8 citation statements)

References 61 publications

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“…Solvents for the synthesis of substrates were dried over Molecular Sieves 4A (Wako) prior to use. Rh(III) complexes [Cp E RhCl 2 ] 2 , 1a , and 1b , benzamides 2a , 2b , 2e , 2f , 2g , 2h , and 2i , and alkene 3c have already been reported. All other reagents were obtained from commercial sources and used as received.…”

Section: Methodsmentioning

confidence: 99%

Aerobic Oxidative Cross-Coupling of Substituted Acrylamides with Alkenes Catalyzed by an Electron-Deficient CpRh^III Complex

2019

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It has been established that an electrondeficient CpRh III complex, bearing two ester moieties on the Cp ring, [Cp E Rh III ], catalyzes the aerobic oxidative cross coupling of substituted acrylamides with both activated and unactivated alkenes, leading to (2Z,4E)-dienamides, at relatively low temperature (80 °C). Importantly, tertiary, secondary, and primary amide directing groups could equally be used in this catalysis. The mechanistic studies revealed that the electron-deficient nature of the Cp E Rh III complex facilitates the turnover-limiting vinylic C−H bond cleavage of the acrylamides.

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Section: Methodsmentioning

confidence: 99%

Aerobic Oxidative Cross-Coupling of Substituted Acrylamides with Alkenes Catalyzed by an Electron-Deficient CpRh^III Complex

2019

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“…Recently, the groups of Charette, Maulide, and Huang have published numerous related works on amide modification and transformation atop this foundation. On the basis of a long-standing interest, our group has also employed the Tf 2 O-activated amide in the crucial process of producing high-bioactivity organic skeletons . Mechanistic research has demonstrated that the keteniminium ion with a high electrophilic reactivity was generated when the amides were activated by Tf 2 O and pyridines (Scheme ).…”

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confidence: 99%

Formation of o-Allyl- and Allenyl-Modified Amides via Intermolecular Claisen Rearrangement

Niu

et al. 2021

Org. Lett.

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We developed a new transition-metal-free intermolecular Claisen rearrangement process to introduce allyl and allenyl groups into the α position of tertiary amides. In this transformation, amides were activated by trifluoromethanesulfonic anhydride to produce the keteniminium ion intermediates that exhibit strong electrophilic activity. This atom-economical process delivers α position-modified amides under mild conditions in moderate to good yields and showcases a broad substrate compatibility.

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“…The use of trimethylsilyl azide (TMSN 3 ) instead of hydrazoic acid for many transformations has gained attention since TMSN 3 is less hazardous [26,27]. Some recent studies employ this reagent in the Schmidt synthesis of tetrazoles from ketones that are smaller in size and simpler than the steroidal ketones in this work [28,29]. For the synthesis of steroidal tetrazoles, most often 1,3-dipolar cycloadditions are being used.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of new bile acid-fused tetrazoles using the Schmidt reaction

Škorić¹,

Klisurić²,

Jakimov³

et al. 2021

Beilstein J. Org. Chem.

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A practical and high-yielding Schmidt reaction for the synthesis of fused tetrazoles from bile acid precursors was developed. Mild reaction conditions using TMSN3 instead of hydrazoic acid as an azide source produced good yields of the desired tetrazoles. These conditions could be applied to other steroidal precursors. Additionally, an improved methodology for the synthesis of different ketone and enone precursors from cholic acid, deoxycholic acid, and chenodeoxycholic acid was established. Newly obtained tetrazole derivatives were characterized by NMR and X-ray diffraction spectroscopy. In a number of cases, preliminary antiproliferative tests of new compounds showed strong and selective activity towards certain tumor cell lines.

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Transition-metal-free multinitrogenation of amides by C–C bond cleavage: a new approach to tetrazoles

Cited by 24 publications

References 61 publications

Aerobic Oxidative Cross-Coupling of Substituted Acrylamides with Alkenes Catalyzed by an Electron-Deficient CpRh^III Complex

Aerobic Oxidative Cross-Coupling of Substituted Acrylamides with Alkenes Catalyzed by an Electron-Deficient CpRh^III Complex

Formation of o-Allyl- and Allenyl-Modified Amides via Intermolecular Claisen Rearrangement

Synthesis of new bile acid-fused tetrazoles using the Schmidt reaction

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Transition-metal-free multinitrogenation of amides by C–C bond cleavage: a new approach to tetrazoles

Cited by 24 publications

References 61 publications

Aerobic Oxidative Cross-Coupling of Substituted Acrylamides with Alkenes Catalyzed by an Electron-Deficient CpRhIII Complex

Aerobic Oxidative Cross-Coupling of Substituted Acrylamides with Alkenes Catalyzed by an Electron-Deficient CpRhIII Complex

Formation of o-Allyl- and Allenyl-Modified Amides via Intermolecular Claisen Rearrangement

Synthesis of new bile acid-fused tetrazoles using the Schmidt reaction

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Aerobic Oxidative Cross-Coupling of Substituted Acrylamides with Alkenes Catalyzed by an Electron-Deficient CpRh^III Complex

Aerobic Oxidative Cross-Coupling of Substituted Acrylamides with Alkenes Catalyzed by an Electron-Deficient CpRh^III Complex