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<p>This study theoretically investigated the selectivity and reactivity in the 32CA reaction of C,N-diarylnitrone (<b>X1)</b> with arylallene (<b>X2)</b> and N-aryl-C-carbamoyl nitrone (<b>B1)</b> with methyl buta-2,3-dienoate (<b>B2)</b>, leading to methylideneisoxazolidine. We employed density functional theory (DFT) at the ωB97XD/6-311+G(d,p). The 32CA reaction of <b>X1 </b>to <b>X2</b> is a one-step mechanism, with path A being the most kinetically favored, leading to the formation of 5-methylideneisoxazolidine diastereoisomeric pairs (<b>P3A</b> + <b>P4A</b>). Substitutions of –CN and -OCH<sub>3</sub> on <b>X2</b> influence the regioselectivity of the cycloaddition process. CN substitution gives the 5-methylideneisoxazolidine cycloadduct, while OCH<sub>3</sub> substitution gives the 4-methylideneisoxazolidine. The reaction of <b>B1</b> with <b>B2</b> occurs at the internal C=C olefinic bond to regioselectively yield the 5-methylideneisoxazolidine adduct. Theoretical computations suggest that the phenyl group on <b>X2</b> behaves as an electron-withdrawing group. The GEDT values for the 32CA of <b>X1</b> to <b>X2</b> exhibit a nonpolar character, classified as REDF, while those involving <b>B1</b> to <b>B2</b> display a slightly polar character, classified as FEDF. </p>

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[3 + 2] cycloaddition reactions of C, N-diarylnitrone to arylallene and N-aryl-C-carbamoyl nitrones to methyl buta-2, 3-dienoate. A theoretical study of reactivity, site, and regio-selectivity

  • 期刊论文

  • 发表日期：

    2025年12月15日

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  • Komla Emmanuel Oyetey,
  • Albert Aniagyei,
  • Elliot S. Menkah,
  • Caroline R. Kwawu,
  • Collins Obuah,
  • Hawa Osman,
  • Evans Adei

摘要

This study theoretically investigated the selectivity and reactivity in the 32CA reaction of C,N-diarylnitrone (X1) with arylallene (X2) and N-aryl-C-carbamoyl nitrone (B1) with methyl buta-2,3-dienoate (B2), leading to methylideneisoxazolidine. We employed density functional theory (DFT) at the ωB97XD/6-311+G(d,p). The 32CA reaction of X1 to X2 is a one-step mechanism, with path A being the most kinetically favored, leading to the formation of 5-methylideneisoxazolidine diastereoisomeric pairs (P3A + P4A). Substitutions of –CN and -OCH3 on X2 influence the regioselectivity of the cycloaddition process. CN substitution gives the 5-methylideneisoxazolidine cycloadduct, while OCH3 substitution gives the 4-methylideneisoxazolidine. The reaction of B1 with B2 occurs at the internal C=C olefinic bond to regioselectively yield the 5-methylideneisoxazolidine adduct. Theoretical computations suggest that the phenyl group on X2 behaves as an electron-withdrawing group. The GEDT values for the 32CA of X1 to X2 exhibit a nonpolar character, classified as REDF, while those involving B1 to B2 display a slightly polar character, classified as FEDF.