作者:David M. Lemal、Dayong Sang、Sudharsanam Ramanathan
DOI:10.1021/jo9015562
日期:2009.10.16
In the absence of significant steric effects, Diels−Alder reactions of the title quinone generally take place with preservation of configuration, and are therefore probably concerted. However, hybrid density functional calculations indicate that often these reactions are highly asynchronous. Steric hindrance can result in reaction at quinone oxygen instead of carbon. Preference for endo over exo cycloaddition
在没有显着的空间效应的情况下,标题醌的Diels-Alder反应通常在保持构型的情况下发生,因此很可能是一致的。但是,混合密度泛函计算表明这些反应通常是高度异步的。立体阻碍可导致在醌氧而非碳下反应。观察到内向优先于外环外加成,并且在外向过渡态中通过排斥性次级轨道相互作用而得到加强。