众所周知,Diels—Alder 反应是合成六园环最重要的合成反应之一,不仅同时形成两个键而且具备良好的立体特征。一方面,在分子内进行的这种 Diels—Aider反应,即所谓分子内 Diels—Alder 反应,与分子间的反应相比较,从熵的方面看来, It is well-known that Diels-Alder reaction is one of the most important synthetic reactions in the synthesis of six rings, which not only forms two bonds simultaneously but also has good stereoscopic characteristics. On the one hand, this Diels-Aider reaction in the molecule, the so-called intramolecular Diels-Alder reaction, compared with the intermolecular reaction, from the perspective of entropy,