• Title/Summary/Keyword: azomethine ylide

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Silyl-Tranfer Photoreactions of Trimethylsilylmethyl Substituted Acyclic N-Sulfonylbenzamides

  • Oh, Sun-Wha
    • Journal of Photoscience
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    • v.12 no.2
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    • pp.63-66
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    • 2005
  • The azomethine ylide forming photoreaction has been explored by probing the excited state chemistry of several N-trimethylsilylmethyl substituted cyclic and acyclic imides and amide analogs. N-[(Trimethylsilyl)methyl]-N-mesylbenzamide (5) undergoes the excited state C to O silyl migration reaction to produce azomethine ylide intermediate 13. This ylide undergoes electrocyclization to form transient aziridine intermediate 14 which react further by ring opening to generate N-phenacylamine product 10. On the other hand, photolysis of N-[N-mesyl-N-(trimethylsilyl)methyl]aminoethyl-N-mesylbenzamide (8) brings about desilylation resulting in the production of dimer 17.

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Dipole-Forming Photochemical Group Transfer Reactions of Phthalimides and ${\alpha}-Ketoamides$

  • Yoon, Ung-Chan;Mariano Patrick S.
    • Journal of Photoscience
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    • v.12 no.3
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    • pp.155-162
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    • 2005
  • Results of studies of SET-promoted dipole-forming photochemical group transfer reactions of phthalimide and ${\alpha}-ketoamide$ derivatives are discussed. Azomethine ylide forming photochemical reactions, which are initiated by intramolecular SET from tethered silylmethyl-, carboxymethyl-, and ${\beta}-hydroxyethyl$ containing electron donors to excited states of phthalimides, related maleimides, and conjugated imides, are presented first. Following this, investigations of regioselective 1,4-dipole forming photochemical reactions of N-trialkylsilylmethyl- and N-trialkylstannyl-${\alpha}$-ketoamides are described.

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Azomethine Yilde Forming Photoreaction of N-(Tributylstannyl)methylphthalimide (N-(트리부틸스탄일)메틸프탈이미드의 아조메틴 일리드 형성 광화학 반응)

  • Jeong, Ho-Cheol;Park, Ki-Hyun;Park, Hea-Jung;Cho, Dae-Won;Yoon, Ung-Chan
    • Journal of the Korean Chemical Society
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    • v.53 no.3
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    • pp.302-307
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    • 2009
  • Investigation was conducted to examine whether photochemical reaction of N-(tributylstannyl)- methylphthalimide generates an azomethine ylide intermediate in its excited state as its silyl derivative N-(trimethylsilyl)methylphthalimide which has been observed to form an azomethine ylide. The irradiation of N-(tributylstannyl)methylphthalimide in $D_2O-CH_3$CN generates mono-deuterated N-methylphthalimide as an exclusive product which supports the efficient generation of azomethine ylide intermediate and its trapping by water molecule through a proto-destannylation pathway. However the generated tributylstannyl subsitiuted ylide was not observed to be trapped with a dipolarophile such as methyl acrylate and acrylonitrile present in the reactions which is in contrast with the ylide from N-(trimethylsilyl)methylphthalimide.

Synthesis of Oligoquinoline Dendronized Fullerenes for Potential Use in Organic Photovoltaic Devices

  • Kwon, Tae-Woo;Jenekhe, Samson A.
    • Bulletin of the Korean Chemical Society
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    • v.33 no.8
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    • pp.2703-2706
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    • 2012
  • New C60 fullerenes derivatives [G1]-C60 (1) and [G2]-C60 (2) comprising of phenylenevinylene bridges and phenylquinoline peripheral surface groups were synthesized by 1,3-dipolar cycloaddition reaction of fullerene C60 with azomethine ylide in situ generated from [Gx]-CHO dendrons (x = 1 and 2) and sarcosine.

Studies of Silyl-Transfer Photochemical Reactions of N-[(Trimethylsilyl)alkyl]saccharins

  • Cho, Dae-Won;Oh, Sun-Wha;Kim, Dong-Uk;Park, Hea-Jung;Xue, Jin-Ying;Yoon, Ung-Chan;Mariano, Patrick S.
    • Bulletin of the Korean Chemical Society
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    • v.31 no.9
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    • pp.2453-2458
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    • 2010
  • Photochemical studies of N-[(trimethylsilyl)alkyl]saccharins were carried out to investigate their photochemical behavior. Depending on the nature of the substrate and the solvent system employed, reactions of these substances can take place by either SET-promoted silyl migration from carbon to either the amide carbonyl or sulfonyl oxygen or by a N-S homolysis route. The results of the current studies show that an azomethine ylide, arising from a SET-promoted silyl migration pathway, is generated in photoreactions of N-[(trimethylsilyl)methyl]saccharin and this intermediate reacts to give various photoproducts depending on the conditions employed. In addition, irradiation of N-[(trimethylsily)ethyl]saccharin produces an excited state that reacts through two pathways, the relative importance is governed by solvent polarity and protic nature. Finally, photoirradiation of N-[(trimethylsilyl)propyl]saccharin in a highly polar solvent system comprised of 35% aqueous MeOH gives rise to formation of a tricyclic pyrrolizidine and saccharin that generated via competitive SET-promoted silyl transfer and $\gamma$-hydrogen abstraction pathways.