New Way to Methylene‐2<i>H</i>‐azirines and Their Use as Powerful Intermediates for the Stereo‐ and Regioselective Synthesis of Compounds with Vinylamine Substructure

Fotsing, Joseph R.; Banert, Klaus

doi:10.1002/ejoc.200600302

Cited by 11 publications

(6 citation statements)

References 51 publications

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“…1), while the eVect is even more striking when Cl-Azirine is considered, for which further shortening of both CAN and CAC bonds is predicted. The stabilizing properties of an electron releasing group at C 3 have been recently shown for methylene-2H-azirines [41] in line with our Wndings.…”

Section: Resultssupporting

confidence: 92%

Substituent effects on the photolysis of methyl 2-carboxylate substituted aliphatic 2H-azirines

Gómez‐Zavaglia

Kaczor

Cardoso

et al. 2007

Journal of Molecular Structure

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In this study, the UV induced photochemical reactions of two 2H-azirines -methyl 2-chloro-3-methyl-2H-azirine-2-carboxylate (MCMAC) and methyl 3-methyl-2H-azirine-2-carboxylate (MMAC) -isolated in argon matrices are compared. For both compounds, irradiation with > 235 nm led to observation of two primary photoprocesses: (a) CAC bond cleavage, with production of nitrile ylides (P1-type products), and (b) CAN bond cleavage, with production of methylated ketene imines (P2-type products). However, subsequent photoprocesses were found to be diVerent in the two cases. In MCMAC, both primary photoproducts were shown to undergo further reactions: P1-type products decarboxylate, giving [(1-chloroethylidene)imino]ethanide, which bears a CBN + BC ¡ group (P3-type product); P2-type products decarbonylate, yielding a substituted ylidene methanamine (P4-type product). In MMAC, only P2-type primary photoproducts appeared to react, undergoing decarbonylation or decarboxylation (both reactions leading to P4-type products), whereas P1-type products were found to be non-reactive. The non-observation of any secondary photoproduct resulting from photolysis of P1-MMAC revealed the higher photostability of this species when compared with the corresponding photoproduct obtained from MCMAC.The CAN photochemical cleavage is an unusual process in aliphatic 2H-azirines. In the studied compounds, its preference over the commonly observed CAC azirine-ring bond photocleavage is attributed to the presence of electron withdrawing substituents (methylcarboxy group in both azirines and also the chlorine atom in MCMAC), which accelerates intersystem crossing towards the triplet state from where the cleavage of the CAN bond takes place. The lack of the chlorine atom in MMAC may be partially compensated by the sig-niWcantly higher stabilization of the P2-type photoproduct derived from this molecule (ca. ¡52 kJ mol ¡1 ) relatively to the reactant, when compared to that obtained from MCMAC (ca. ¡26 kJ mol ¡1 ). Nevertheless, the obtained results indicate that the methylcarboxy substituent plays the most important role in determining the photochemical behavior of these aliphatic 2H-azirines, in particular the preference they exhibit for the unusual CAN bond cleavage over the "classic" CAC bond cleavage.

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Section: Resultssupporting

confidence: 92%

Substituent effects on the photolysis of methyl 2-carboxylate substituted aliphatic 2H-azirines

Gómez‐Zavaglia

Kaczor

Cardoso

et al. 2007

Journal of Molecular Structure

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“…Subsequent ring opening to form α-aminophosphine oxide acetals 4 occurs with complete site selectivity at N–C3 bond, after nucleophilic attack of a second molecule of methanol. This behavior has been previously observed in the addition of methanol to methylene-2 H -azirines [ 47 ], or more recently to an aryl substituted 2 H -azirine [ 48 ].…”

Section: Resultssupporting

confidence: 70%

Synthesis of α-Aminophosphonic Acid Derivatives Through the Addition of O- and S-Nucleophiles to 2H-Azirines and Their Antiproliferative Effect on A549 Human Lung Adenocarcinoma Cells

et al. 2020

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This work reports a straightforward regioselective synthetic methodology to prepare α-aminophosphine oxides and phosphonates through the addition of oxygen and sulfur nucleophiles to the C–N double bond of 2H-azirine derivatives. Determined by the nature of the nucleophile, different α-aminophosphorus compounds may be obtained. For instance, aliphatic alcohols such as methanol or ethanol afford α-aminophosphine oxide and phosphonate acetals after N–C3 ring opening of the intermediate aziridine. However, addition of 2,2,2-trifluoroethanol, phenols, substituted benzenthiols or ethanethiol to 2H-azirine phosphine oxides or phosphonates yields allylic α-aminophosphine oxides and phosphonates in good to high general yields. In some cases, the intermediate aziridine attained by the nucleophilic addition of O- or S-nucleophiles to the starting 2H-azirine may be isolated and characterized before ring opening. Additionally, the cytotoxic effect on cell lines derived from human lung adenocarcinoma (A549) and non-malignant cells (MCR-5) was also screened. Some α-aminophosphorus derivatives exhibited very good activity against the A549 cell line in vitro. Furthermore, selectivity towards cancer cell (A549) over non-malignant cells (MCR-5) has been detected in almost all compounds tested.

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“…However, in the presence of a base, conjugate addition of methanol occurred instead, affording the corresponding vinyl azide, which was photolyzed to produce the azirine 457 . The γ-methyl derivative of 157 behaved similarly, while the γ-azido allenic sulfone 458 formed azirine 459 in low yield, along with products of further photolysis . The unusual borirene 461 was prepared by Eisch et al from acetylenic sulfone 11 , by conversion to the ethynylborane 460 , followed by photolysis.…”

Section: Synthesis Of Three-membered Rings From Unsaturated Sulfonesmentioning

confidence: 99%

Cycloadditions and Cyclizations of Acetylenic, Allenic, and Conjugated Dienyl Sulfones

2010

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Introduction 4499 2. Diels-Alder Cycloadditions 4499 2.1. Unsaturated Sulfones as Dienophiles 4499 2.1.1. Early Studies 4499 2.1.2. Aromatization of Cycloaddition Products of Acetylenic Sulfones 4501 2.1.3. Iterative Diels-Alder and Ramberg-Backlund Reactions of Chloroalkylsulfonyl Allenes 4502 2.1.4. Diels-Alder Cycloadditions of Bis(sulfonyl)acetylenes and Their Equivalents 4502 2.1.5. Diels-Alder Cycloadditions of Acetylenic Sulfones Containing Heteroatom Substituents 4503 2.1.6. Diels-Alder Reactions of Dienyl Sulfones as Dienophiles 4504 2.1.7. Diels-Alder Reactions of Unsaturated Sulfones with Pyrroles 4505 2.1.8. Diels-Alder Reactions of Unsaturated Sulfones with Furans and Isobenzofurans 4507 2.1.9. Miscellaneous Cycloadditions 4508 2.2. Dienyl Sulfones As the Diene Components in Diels-Alder Reactions 4509 2.2.1. 1-Sulfonyl Derivatives † Dedicated to Professor David N. Harpp, for his inspiring contributions as a teacher, mentor and scholar.

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New Way to Methylene‐2H‐azirines and Their Use as Powerful Intermediates for the Stereo‐ and Regioselective Synthesis of Compounds with Vinylamine Substructure

Cited by 11 publications

References 51 publications

Substituent effects on the photolysis of methyl 2-carboxylate substituted aliphatic 2H-azirines

Substituent effects on the photolysis of methyl 2-carboxylate substituted aliphatic 2H-azirines

Synthesis of α-Aminophosphonic Acid Derivatives Through the Addition of O- and S-Nucleophiles to 2H-Azirines and Their Antiproliferative Effect on A549 Human Lung Adenocarcinoma Cells

Cycloadditions and Cyclizations of Acetylenic, Allenic, and Conjugated Dienyl Sulfones

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