Syntheses of pentamethylcyclopentadienylcobalt(III) compounds and reactions of [Co(C5Me5)(solvent)3]X2(solvent = acetonitrile or acetone, X = BF4or PF6)

Fairhurst, Geoffrey; White, Colin

doi:10.1039/dt9790001524

Cited by 25 publications

(15 citation statements)

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“…Although further minor modification of the reaction conditions was unfruitful, screening of Cp*Co III catalysts led to improvement (entries 4–6). For our desired reaction, the [Cp*Co III (CH 3 CN) 3 ]X 2 catalysts 1 b‐X had higher reactivity and selectivity than the Cp*Co III ‐arene catalyst 1 a , and the best catalyst 1 b‐SbF 6 afforded 69 % yield (entry 6). We screened the reaction conditions again using 1 b‐SbF 6 and determined that 5 mol % KOAc was optimal (entry 7) to give 4 aa in 80 % yield (74 % isolated yield).…”

Section: Methodssupporting

confidence: 68%

Stereoselective Synthesis of Tetrasubstituted Alkenes via a Cp*Co^III‐Catalyzed C−H Alkenylation/Directing Group Migration Sequence

et al. 2017

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A highly atom economical and stereoselective synthesis of tetrasubstituted α,β-unsaturated amides was achieved by a Cp*Co -catalyzed C-H alkenylation/directing group migration sequence. A carbamoyl directing group, which is typically removed after C-H functionalization, worked as an internal acylating agent and migrated onto the alkene moiety of the product. The directing group migration was realized with the Cp*Co catalyst, while a related Cp*Rh catalyst did not promote the migration process. The product was further converted into two types of tricyclic compounds, one of which had fluorescent properties.

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Section: Methodssupporting

confidence: 68%

Stereoselective Synthesis of Tetrasubstituted Alkenes via a Cp*Co^III‐Catalyzed C−H Alkenylation/Directing Group Migration Sequence

et al. 2017

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“…Thus, we investigated the reaction in more detail to identify a suitable cobalt‐based catalyst. We assumed that the inferior activity of the [Cp*Co(III)(C 6 H 6 )](PF 6 ) 2 complex could be due to the thermal instability of the PF 6 − ion under the present reaction conditions 14. Trials to exchange the counter ion of the cationic Cp*Co(III)(C 6 H 6 ) complex were not successful due to problems in the purification step.…”

Section: Optimization Studiesmentioning

confidence: 97%

Air‐Stable Carbonyl(pentamethylcyclopentadienyl)cobalt Diiodide Complex as a Precursor for Cationic (Pentamethylcyclopentadienyl)cobalt(III) Catalysis: Application for Directed C‐2 Selective CH Amidation of Indoles

et al. 2014

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The readily available carbonyl(pentamethylcyclopentadienyl)cobalt diiodide complex [Cp*Co(CO)I 2 ] was successfully utilized as the precursor of a cationic cobaltA C H T U N G T R E N N U N G (III) active catalyst for directed C À H bond functionalization. The complex Cp*Co(CO)I 2 (2.5-1.25 mol%), in combination with silver hexafluoroantimonate (AgSbF 6) and potassium acetate (KOAc), efficiently catalyzed the directed C-2 selective amidation of indoles with sulfonyl azides, and the corresponding products were obtained in 85-98 % yield.

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“…In these reactions, the PF 6 anion is not suitable, possibly due to instability. 24 Since Cp*Co(CO)I 2 and [Cp*CoI 2 ] 2 are easily prepared in good yield and enable the investigation of counteranion effects, 22,23,25 these precursors, combined with various silver salts, have become the most popular Cp*Co III catalysts. 26 Scheme 6 C2-selective amidation of indoles using azides…”

Section: C-h Addition Reactions To Polar Double Bondsmentioning

confidence: 99%

Cp*CoIII-Catalyzed C–H Functionalization and Asymmetric Reactions Using External Chiral Sources

Yoshino¹,

Matsunaga²

2019

Synlett

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This account describes Cp*CoIII-catalyzed C–H functionalization reactions developed in our group between 2013 and 2018. Cp*CoIII catalysts not only serve as inexpensive alternatives to Cp*RhIII catalysts but also exhibit unique reactivity and selectivity in several transformations. In the latter part of this review, we introduce catalytic asymmetric C–H functionalization reactions using achiral RhIII or CoIII catalysts with chiral disulfonates or carboxylic acids as external chiral sources.1 Introduction and Overview2 Cp*CoIII-Catalyzed C–H Functionalization Reactions2.1 C–H Addition Reactions to Polar Double Bonds2.2 Cp*Co(CO)I2 and [Cp*CoI2]2 Precursors for the C2-selective C–H Amidation of Indoles2.3 C–H Functionalization of Carbamoyl-Protected Indoles Using Alkynes2.4 C–H Allylation Using Allyl Alcohols2.5 Cyclization Reactions of O-Acyloximes and Alkynes2.6 Other Miscellaneous Reactions3 Enantioselective C–H Functionalization Reactions by Hybrid Catalysis3.1 Cp*RhIII/Chiral Disulfonate Catalysts for the Enantioselective C–H Addition to Enones3.2 Enantioselective C–H Cleavage Using Chiral Carboxylic Acids4 Summary and Perspective

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Syntheses of pentamethylcyclopentadienylcobalt(III) compounds and reactions of [Co(C5Me5)(solvent)3]X2(solvent = acetonitrile or acetone, X = BF4or PF6)

Cited by 25 publications

References 0 publications

Stereoselective Synthesis of Tetrasubstituted Alkenes via a Cp*Co^III‐Catalyzed C−H Alkenylation/Directing Group Migration Sequence

Stereoselective Synthesis of Tetrasubstituted Alkenes via a Cp*Co^III‐Catalyzed C−H Alkenylation/Directing Group Migration Sequence

Air‐Stable Carbonyl(pentamethylcyclopentadienyl)cobalt Diiodide Complex as a Precursor for Cationic (Pentamethylcyclopentadienyl)cobalt(III) Catalysis: Application for Directed C‐2 Selective CH Amidation of Indoles

Cp*CoIII-Catalyzed C–H Functionalization and Asymmetric Reactions Using External Chiral Sources

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Syntheses of pentamethylcyclopentadienylcobalt(III) compounds and reactions of [Co(C5Me5)(solvent)3]X2(solvent = acetonitrile or acetone, X = BF4or PF6)

Cited by 25 publications

References 0 publications

Stereoselective Synthesis of Tetrasubstituted Alkenes via a Cp*CoIII‐Catalyzed C−H Alkenylation/Directing Group Migration Sequence

Stereoselective Synthesis of Tetrasubstituted Alkenes via a Cp*CoIII‐Catalyzed C−H Alkenylation/Directing Group Migration Sequence

Air‐Stable Carbonyl(pentamethylcyclopentadienyl)cobalt Diiodide Complex as a Precursor for Cationic (Pentamethylcyclopentadienyl)cobalt(III) Catalysis: Application for Directed C‐2 Selective CH Amidation of Indoles

Cp*CoIII-Catalyzed C–H Functionalization and Asymmetric Reactions Using External Chiral Sources

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Stereoselective Synthesis of Tetrasubstituted Alkenes via a Cp*Co^III‐Catalyzed C−H Alkenylation/Directing Group Migration Sequence

Stereoselective Synthesis of Tetrasubstituted Alkenes via a Cp*Co^III‐Catalyzed C−H Alkenylation/Directing Group Migration Sequence