Preparation of <sup>13</sup>C<sub>4</sub>-6-Methyl Anthranilic Ester via a Diels−Alder-Type Process. An Experimental and Theoretical Study to Characterize an Unexpected Isotope Exchange

Alonso‐Gómez, José Lorenzo; Pazos, Yolanda; Navarro‐Vázquez, Armando; Lugtenburg, J.; Cid, Marı́a Magdalena

doi:10.1021/ol051433f

Cited by 13 publications

(2 citation statements)

References 14 publications

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“…Vinylketenimine 284 reacts by a Diels–Alder [4 + 2] cycloaddition with the allenyl ester 285 leading to the aniline 286 , but the use of 13 C labeling showed that scrambling of the carbons a and b occurred as explained by reversible formation of cyclobutane 287a , which interconverts with diradical 287b and the alternative diradical with a radical site at C a (Scheme ) …”

Section: Ketenimines As Reactive Intermediatesmentioning

confidence: 99%

Ketenes and Other Cumulenes as Reactive Intermediates

2013

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Section: Ketenimines As Reactive Intermediatesmentioning

confidence: 99%

Ketenes and Other Cumulenes as Reactive Intermediates

2013

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“…As an additional benefit, diverse ester groups can be introduced right from the start, e.g. benzyl groups as in 22b or long alkyl chains as in 22c that make these cages amphiphilic (from the corresponding benzyl 49 or dodecyl esters). Saponification and acidic workup leads to the decarboxylated cage compound 23 (α-demethylated analogue of 20) with similar δdamascone release properties.…”

Section: Two Norrish Type II Approaches For the Model Enone δ-Damasconementioning

confidence: 99%

Photocaged Hydrocarbons, Aldehydes, Ketones, Enones, and Carboxylic Acids and Esters that Release by the Norrish II Cleavage Protocol and Beyond: Controlled Photoinduced Fragrance Release

et al. 2016

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Five families of caged fragrance compounds that allow the storage and release of the following small volatile organic molecules are described: terpene hydrocarbons, aldehydes, ketones, Michael-type α,β-unsaturated enones, and carboxylic acids and esters. These caged molecules are released by photoexcitation via carbonyl-directed hydrogentransfer processes and subsequent CC bond cleavage (Norrish Type II) or by didenitrogenation of diazirines.

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Copper‐Catalyzed One‐Pot Synthesis of 2‐Alkylidene‐1,2,3,4‐ tetrahydropyrimidines

Song

Deng

et al. 2009

Adv Synth Catal

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A one-pot synthesis of N-sulfonyl-2-alkylidene-1,2,3,4-tetrahydropyrimidines via a highly selective and copper-catalyzed multicomponent reaction of sulfonyl azides, terminal alkynes and a,b-unsaturated imines has been developed. The a,b-unsaturated imine substrates could be generated from amines and a,b-unsaturated aldehydes in a one-pot process. The procedure is concise, general and efficient.Keywords: ketenimines; multicomponent reactions; tandem reaction; tetrahydropyrimidines Ketenimines are nitrogen-containing heterocumulenes, which can participate in a variety of organic reactions, [1] such as nucleophilic addition reactions, [2] radical addition reactions, [3] [2 + 2] and [4 + 2] cycloaddition reactions [4] and sigmatropic rearrangements.[5]Previously, we [6] and several other groups [7] developed the Cu-catalyzed three-component reactions of sulfonyl azides with terminal alkynes and a number of nucleophiles. The reactions involve a copper-catalyzed azide-alkyne cycloaddtion (CuAAC) and the generation of a ketenimine intermediate. Phosphoryl azides could also serve as a high-yielding type of azide to participate in the reaction.[8] These multicomponent reactions are versatile with regard to the substrate scope and the synthetic applicability. On the basis of these results, we anticipated that the ketenimine intermediate A (Scheme 1), which was in situ generated from terminal alkyne 1a and sulfonyl azide 2a, could react with a,b-unsaturated imine 3a through a nucleophilic cyclization to give tetrahydropyrimidine 4aaa and/or azetidin-2-imine 5aaa, respectively. Since the formation of azetidin-2-imines via the reaction of the ketenimine intermediate with imines has been reported by Whiting and Fokin, [7e] we systematically optimized the reaction leading to the six-membered product and investigated the applicability of this method to a variety of terminal alkynes, sulfonyl azides and a,b-unsaturated imines. Herein, we report the details of this work.Exhaustive studies of the reaction conditions for the synthesis of 4aaa from terminal alkyne 1a, sulfonyl azide 2a and a,b-unsaturated imine 3a showed that CuCl (Table 1, entry 1), CuBr (Table 1, entry 2), and CuI (Table 1, entries 3-14) could catalyze the reaction to result in a mixture of the six-membered product 4aaa and the four-membered product 5aaa, Scheme 1. Copper-catalyzed three-component reaction of alkyne 1a, sulfonyl azide 2a and imine 3a.

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Preparation of ¹³C₄-6-Methyl Anthranilic Ester via a Diels−Alder-Type Process. An Experimental and Theoretical Study to Characterize an Unexpected Isotope Exchange

Cited by 13 publications

References 14 publications

Ketenes and Other Cumulenes as Reactive Intermediates

Ketenes and Other Cumulenes as Reactive Intermediates

Photocaged Hydrocarbons, Aldehydes, Ketones, Enones, and Carboxylic Acids and Esters that Release by the Norrish II Cleavage Protocol and Beyond: Controlled Photoinduced Fragrance Release

Copper‐Catalyzed One‐Pot Synthesis of 2‐Alkylidene‐1,2,3,4‐ tetrahydropyrimidines

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Preparation of 13C4-6-Methyl Anthranilic Ester via a Diels−Alder-Type Process. An Experimental and Theoretical Study to Characterize an Unexpected Isotope Exchange

Cited by 13 publications

References 14 publications

Ketenes and Other Cumulenes as Reactive Intermediates

Ketenes and Other Cumulenes as Reactive Intermediates

Photocaged Hydrocarbons, Aldehydes, Ketones, Enones, and Carboxylic Acids and Esters that Release by the Norrish II Cleavage Protocol and Beyond: Controlled Photoinduced Fragrance Release

Copper‐Catalyzed One‐Pot Synthesis of 2‐Alkylidene‐1,2,3,4‐ tetrahydropyrimidines

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Preparation of ¹³C₄-6-Methyl Anthranilic Ester via a Diels−Alder-Type Process. An Experimental and Theoretical Study to Characterize an Unexpected Isotope Exchange