Development of a Pd-catalyzed Selective synthetic Method for Polysubstituted Benzenes

本论文基于炔与π-烯丙基钯配合物的关键反应，发展了一种新的多取代苯的合成方法。（1）虽然关于炔插入π-烯丙基钯配合物的报道很少，但我们发现，如果配合物具有弱配体，则插入顺利进行，并将其用于催化。在催化反应中，烯丙基化试剂上离去基团的配位能力是非常重要的。使用甲苯磺酸烯丙酯作为烯丙基化化合物，反应有效地进行。在该反应中，一分子甲苯磺酸烯丙酯和两分子内炔以中到高产率得到五取代苯。使用末端，炔，三取代苯形成。（2）本研究的结果与炔插入π-烯丙基钯配合物的反应机理一致。（3）对甲苯磺酸酐的加入使烯丙醇的使用成为可能。这一事实增加了催化剂的可用性，因为烯丙醇比其他烯丙基化合物更便宜且更容易获得。（4）在一氧化碳气氛下进行反应，得到环戊烯酮而不是芳烃。用烯烃代替炔烃，烯丙基化合物发生烯丙基烯基化反应。

In this study, we developed a novel synthetic method for polysubstituted benzenes, which is based on the key reaction of alkynes with π-allylpalladium complexes.(1)While there is few reports on the insertion of alkynes into π-allylpalladium complexes, we found that the insertion proceeds smoothly if the complex has a weak ligand, and utilized it for catalysis. In the catalysis, the ligating ability of leaving groups on allylating agents is quite important. Using allyl tosylate as an allylating compound, the reaction proceeded effectively. In this reaction, penta-substituted benzenes were obtained form one molecule of allyl tosylate and two moleculae of internal alkynes in moderate to high yields. Using terminal, alkynes, trisubstituted benzenes were formed.(2)All results in this study are consistent with the mechanism that includes the insertion of alkynes into π-allylpalladium complexes as a key step.(3)The addition of p-toluenesulfonic anhydride made an employment of allylis alcohols possible. The fact increases the usability of the catalysis because allylic alcohols are cheaper and more available than other allylic compounds.(4)Being carried out under carbon monoxide atmosphere, the reaction afforded cyclopentenones instead of arenes. Using alkenes instead of alkynes, the allylic alkenylation of allylic compounds took place.