Synthesis of highly functionalized biologically active molecules utilizing a cascade cyclization of propargylic esters

已知炔丙基酯与钯络合物反应产生炔丙基钯络合物，其在软亲核试剂存在下进一步引起各种转化以产生相应的产物。其中，钯催化的炔丙酯与双亲核试剂的环化反应是一步合成功能化环状分子的有效方法之一。在本研究中，我们研究了钯催化的炔丙基酯与双亲核试剂的反应，合成高度官能化的杂环分子。结果，我们的努力导致了1）通过炔丙基酮酯的反应合成四取代呋喃和2）通过炔丙基碳酸酯与4-羟基-2-吡喃酮的反应合成呋喃并[3，2-c]吡喃-4-酮衍生物的发展。

It is known that propargylic esters react with palladium complex leading to propargylpalladium complexes, which further cause various transformations in the presence of soft nucleophiles to produce the corresponding products. Among them, palladium-catalyzed cyclization of propargylic esters with bis-nucleophiles is one of the useful methodologies for the construction of functionalized cyclic molecules in one step. In this study, we examined the synthesis of highly functionalized heterocyclic molecules by the palladium-catalyzed reactions of propargylic esters with bis-nucleophiles. As the result, our effort has led to the development of 1) the synthesis of tetrasubstituted furans by a reaction of propargyl keto esters and 2) the synthesis of furo[3,2-c]pyran-4-one derivatives by a reaction of propargyl carbonates with 4-hydroxy-2-pyrones.