Universidad de Alcalá, Departamento de Química Analítica, Química Física e Ingeniería Química, Grupo de Reactividad y Estructura Molecular (RESMOL), Alcalá de Henares 28806, Madrid, Spain.
Instituto de Investigación Química ''Andrés M. del Río'' (IQAR), Universidad de Alcalá, Alcalá de Henares 28806, Madrid, Spain.
J Org Chem. 2022 Oct 7;87(19):12586-12595. doi: 10.1021/acs.joc.2c00720. Epub 2022 Sep 27.
In this work, we demonstrate that the forbidden oxirane-type photoproduct (the cyclopropyl ketone photoproduct is the allowed one) of the oxa-di-π-methane photorearrangement can be obtained by mechanochemical control of the photoreactions. This control is achieved by the application of simple force pairs rationally chosen. By analyzing in detail the effect of the applied forces on this photoreaction, it comes to light that the mechanical action affects the diverse properties of the oxa-di-π-methane rearrangement, modifying all the steps of the reaction: (i) the initial ground-state conformers' distribution becomes affected; (ii) the new conformational population makes the triplet excitation process to be changed, responding to the magnitude of the applied force; (iii) the stability of the different intermediates along the triplet pathway also becomes affected, changing the dynamical behavior of the system and the reaction kinetics; and (iv) the intersystem crossing also becomes strongly affected, making the forbidden oxirane-type photoproduct to decay more efficiently to the ground state. All these changes provide a complex scenario where a detailed study of the effect of applied forces is necessary in order to predict its overall effect on the photoreactivity.
在这项工作中，我们证明了通过机械化学控制光反应，可以获得受阻的环氧乙烷型光产物（环丙基酮光产物是允许的）。这种控制是通过合理选择简单的力偶来实现的。通过详细分析所施加力对这种光反应的影响，我们发现机械作用会影响氧杂二-π-甲烷重排的各种性质，改变反应的所有步骤：（i）初始基态构象的分布受到影响；（ii）新的构象种群使三重态激发过程发生变化，响应施加力的大小；（iii）沿三重态途径的不同中间体的稳定性也受到影响，改变了系统的动力学行为和反应动力学；（iv）系间窜越也受到强烈影响，使受阻的环氧乙烷型光产物更有效地衰减到基态。所有这些变化提供了一个复杂的情景，需要对施加力的影响进行详细研究，以预测其对光反应性的整体影响。
