ABSTRACT

Inverse electron demand Diels–Alder reactions have gained comprehensive attraction in recent years. Accordingly, the synthetic approaches for one of the coupling partners, namely s-tetrazine, have been extensively investigated. Generally, the main synthetic method of s-tetrazine relied on the condensation of two nitriles to give the corresponding symmetric/asymmetric tetrazines with moderate to excellent yields. However, the practical synthesis route and commercial/synthetic availability of the feedstock nitriles are still elusive. It is therefore probably worth summarizing the existing methods and typical biological applications that have been demonstrated in recent years. In brief, this overview will be split into three parts. First, we will summarize the typical approaches toward the synthesis of s-tetrazines till now. Then, we will provide the representative bio-orthogonal reactions by the combination of s-tetrazines with unsaturated compounds under physiological conditions. Eventually, we will propose a direction for the practical and efficient synthesis of s-tetrazine.

摘要

逆电子需求Diels–Alder反应近年来获得了广泛的关注。因此，已经广泛研究了偶联伴侣之一即s-四嗪的合成方法。通常，s的主要合成方法-四嗪依靠两个腈的缩合以中等至优异的产率得到相应的对称/不对称四嗪。然而，原料腈的实际合成路线和商业/合成可用性仍然难以捉摸。因此，可能有必要总结近年来已证明的现有方法和典型的生物学应用。简而言之，此概述将分为三个部分。首先，我们将总结到目前为止合成s-四嗪的典型方法。然后，我们将结合s提供代表性的生物正交反应。-四嗪与生理条件下的不饱和化合物。最终，我们将提出一个实用而有效的合成s-四嗪的方向。