ChemInform Abstract: Imidyl Radicals. Part 2. Radical Addition of N‐Chlorophthalimide and N‐Bromophthalimide to Alkenes.

Kirsch, André; Luening, U.

doi:10.1002/chin.199826151

Cited by 2 publications

(2 citation statements)

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“…Interestingly, a closer look into this experiment revealed that isomerized alkene ( E )- 5h was detected in small amounts under standard reaction conditions. A similar observation was reported in a previously disclosed aminohalogenation reaction and was explained by a possible reversible addition of an amino radical to a double bond. , …”

Section: Resultssupporting

confidence: 86%

“…A similar observation was reported in a previously disclosed aminohalogenation reaction and was explained by a possible reversible addition of an amino radical to a double bond. 29,30 To delve deeper into the electronic dependence of the aminoazidation reaction, a Hammett study was next performed using intermolecular competition experiments. We obtained a slope of ρ = −0.51 (Scheme 6d), which suggests only minor positive charge buildup in the transition state of the product selective step of the reaction.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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Direct Synthesis of Unprotected 2-Azidoamines from Alkenes via an Iron-Catalyzed Difunctionalization Reaction

2020

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Unprotected, primary 2-azidoamines are versatile precursors to vicinal diamines, which are among the most common motifs in biologically active compounds. Herein, we report their operationally simple synthesis through an iron-catalyzed difunctionalization of alkenes. A wide array of alkene substrates are tolerated, including complex drug-like molecules and a tripeptide. Facile derivatizations of the azidoamine group demonstrate the versatility of this masked diamine motif in chemoselective, orthogonal transformations. Applications of the methodology in the concise synthesis of RO 20-1724 and in a formal total synthesis of (±)-hamacanthin B further demonstrate the broad synthetic potential of this highly functional group tolerant reaction.Vicinal diamines are privileged structural motifs encountered across the molecular sciences, particularly in natural products, medicinal chemistry and catalysis. 1 Therefore, the rapid access to this ubiquitous functionality starting from simple hydrocarbon feedstocks, such as alkenes, can dramatically facilitate the synthesis and discovery of functional molecules. Several approaches have been explored to install two vicinal amino groups through the catalytic diamination of alkenes. 2 However, these reactions are still considerably limited when compared to well established methods for the synthesis of other important 1,2-difunctionalized alkanes, such as diols. 3 Besides the scope being often limited to activated alkenes, a more significant limitation is the lack of methods to access a diamine precursor which can be orthogonally transformed into synthetically relevant unsymmetrical diamine products (Scheme 1). Scheme 1. Importance of unsymmetrical vicinal diaminesThe azido group has recently emerged as a convenient amino group surrogate in formal catalytic diamination reactions (Scheme 2). 4 Most notably, Lin 5 and Xu 6 have described elegant electrochemical and iron-catalyzed processes, respectively, for the direct synthesis of diazides starting from a wide variety of alkenes (Scheme 2a). Whereas these reactions are powerful tools to access symmetrical vicinal diamines in two steps, they are less suitable in cases where two chemically distinct amino groups need to be orthogonally synthesized (e. g. through amide coupling), a scenario which is common in target-oriented synthesis. 7 Indeed, diazides suffer from poor regioselectivity upon monoreduction, making the direct synthesis of 2-azidoamines from alkenes highly challenging. 8 catalyzed the desired reaction in good yields using this usually unreactive substrate (Entries 1, 3, 4). The possible catalytic effect of impurities from the iron source was ruled out by a control experiment with a trace metals-based source which Scheme 3. Scope of the aminoazidation reaction Yields are of isolated products; dr determined by 1 H-NMR. a (E)-alkene used. b Purified via column chromatography. c Purified via ammonium salt precipitation. d Starting from an ester bearing a terminal alkene. e See SI for detailed experimental information.

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Section: Resultssupporting

confidence: 86%

Section: ■ Results and Discussionmentioning

confidence: 99%

Direct Synthesis of Unprotected 2-Azidoamines from Alkenes via an Iron-Catalyzed Difunctionalization Reaction

2020

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Photoinduced Addition of Phthalimide to Unactivated Alkynes†

Nájera

Garcı́a-Segura

Pérez‐Inestrosa

et al. 2006

Photochem Photobiol

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Photoexcited phthalimide in equilibrium with its conjugated base produces the regioselective hydrophthalimidation of conjugated alkynes. The vinylphthalimide thus obtained is hydrolyzed to the corresponding carbonyl compound. With unconjugated alkynes, the outcome is a double addition of phthalimide to the triple bond. The reaction is assumed to take place via single electron transfer from either the alkyne or the phthalimide anion to the excited phthalimide as the primary photoprocess.

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ChemInform Abstract: Imidyl Radicals. Part 2. Radical Addition of N‐Chlorophthalimide and N‐Bromophthalimide to Alkenes.

Cited by 2 publications

References 3 publications

Direct Synthesis of Unprotected 2-Azidoamines from Alkenes via an Iron-Catalyzed Difunctionalization Reaction

Direct Synthesis of Unprotected 2-Azidoamines from Alkenes via an Iron-Catalyzed Difunctionalization Reaction

Photoinduced Addition of Phthalimide to Unactivated Alkynes†

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