Sunlamp-irradiated phase-transfer catalysis. 1. Cobalt carbonyl catalyzed SRN1 carbonylations of aryl and vinyl halides

Brunet, Jean Jacques; Sidot, Christian; Caubère, P.

doi:10.1021/jo00156a004

Cited by 94 publications

(28 citation statements)

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“…Along these lines, we tested a set of conditions reported by Caubere and co-workers that employed dicobalt octacarbonyl under highly basic aqueous conditions (5 M NaOH) and UV irradiation. 39 According to the proposed mechanism, 40 such transformations proceed through photoinduced electron- or charge-transfer complexes between aryl halides and [Co(CO) 4 ] − , resulting in the formation of aroylcobalt carbonyl complexes of type I-1 , which should readily collapse to lactam product 1 with concurrent regeneration of catalyst [Co(CO) 4 ] − . Indeed, using Caubere’s protocol we were encouraged to find that (+)-7-deoxypancratistatin ( 1 ) could be observed in low yield, with rest of the mass balance being recovered starting material and an amino acid, likely resulting from subsequent base-induced hydrolysis.…”

Section: Resultsmentioning

confidence: 99%

Enantioselective Synthesis of Isocarbostyril Alkaloids and Analogs Using Catalytic Dearomative Functionalization of Benzene

et al. 2018

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Enantioselective total syntheses of the anticancer isocarbostyril alkaloids (+)-7-deoxypancratistatin, (+)-pancratistatin, (+)-lycoricidine, and (+)-narciclasine are described. Our strategy for accessing this unique class of natural products is based on the development of a Nicatalyzed dearomative trans-1,2-carboamination of benzene. The effectiveness of this dearomatization approach is notable, as only two additional olefin functionalizations are needed to construct the fully decorated aminocyclitol cores of these alkaloids. Installation of the lactam ring has been achieved through several pathways and a direct interconversion between natural products was established via a late-stage C-7 cupration. Using this synthetic blueprint, we were able to produce natural products on a gram scale and provide tailored analogs with improved activity, solubility, and metabolic stability.

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Section: Resultsmentioning

confidence: 99%

Enantioselective Synthesis of Isocarbostyril Alkaloids and Analogs Using Catalytic Dearomative Functionalization of Benzene

et al. 2018

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“…One should keep in mind in discussing of the synthetic role of the reaction that nitroaromatic compounds inhibit the cobalt-catalysed methoxycarbonylation (as we have shown previously for aryl bromides) [20,23,26,27,28]. Preparation of alkoxycarbonyl benzoic acids and benzene dicarboxylic acids using the proposed method is also challenging, since most of the esters are hydrolyzed during the process, and the resulting halogen carboxylate anions are inert in the methoxycarbonylation.…”

Section: Resultsmentioning

confidence: 99%

“…The authors proposed the radical anion mechanism for this reaction. Later it was shown that photochemical initiation can be used in the carbonylation of bromobenzenes instead of a one-electron reducing agent (NaH) [20,26,27,28].…”

Section: Introductionmentioning

confidence: 99%

Cobalt-Catalyzed Methoxycarbonylation of Substituted Dichlorobenzenes as an Example of a Facile Radical Anion Nucleophilic Substitution in Chloroarenes

et al. 2014

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A thorough mechanistic study on cobalt-catalysed direct methoxycarbonylation reactions of chlorobenzenes in the presence of methyl oxirane on a wide range of substrates, including poly-and monochloro derivatives with multiple substituents, is reported. The results demonstrate that the reaction is potentially useful as it proceeds under very mild conditions (t = 62 °C, P CO = 1 bar) and converts aryl chlorides to far more valuable products (especially ortho-substituted benzoic acids and esters) in high yields. This transformation also offers another opportunity for the utilization of environmentally harmful polychlorinated benzenes and biphenyls (PCBs). This study is the first to discover an unexpected universal positive ortho-effect: the proximity of any substituent (including Me, Ph, and MeO groups and halogen atoms) to the reaction centre accelerates the methoxycarbonylation in chlorobenzenes. The effect of the ortho-substituents is discussed in detail and explained in terms of a radical anion reaction mechanism. The advantages of the methoxycarbonylation as a model for the mechanistic study of radical anion reactions are also illustrated.

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“…In 1983, Brunet et al described Co 2 (CO) 8 -catalyzed SRN 1 carbonylations of the same substrates under sunlamp-irradiated phase-transfer conditions [43]. Two benzolactones were synthesized in excellent yields (Scheme 19).…”

Section: Valeralactone Pyran-2-one and Their Derivativesmentioning

confidence: 99%

Palladium-Catalyzed Carbonylative Synthesis of Six-Membered Heterocycles from Aryl Halides

2015

Topics in Heterocyclic Chemistry

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Sunlamp-irradiated phase-transfer catalysis. 1. Cobalt carbonyl catalyzed SRN1 carbonylations of aryl and vinyl halides

Cited by 94 publications

References 1 publication

Enantioselective Synthesis of Isocarbostyril Alkaloids and Analogs Using Catalytic Dearomative Functionalization of Benzene

Enantioselective Synthesis of Isocarbostyril Alkaloids and Analogs Using Catalytic Dearomative Functionalization of Benzene

Cobalt-Catalyzed Methoxycarbonylation of Substituted Dichlorobenzenes as an Example of a Facile Radical Anion Nucleophilic Substitution in Chloroarenes

Palladium-Catalyzed Carbonylative Synthesis of Six-Membered Heterocycles from Aryl Halides

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