By employing only silica as a catalyst, the carboxylative cyclization of a propargylic amine with CO₂ proceeded to afford the corresponding 2-oxazolidinone. MCM-41, which was a mesoporous silica, was found to be the most effective silica for this purpose. Moreover, after the reaction, the MCM-41 catalyst was recovered by filtration and could be reused over ten times without deactivation.

中文翻译：

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二氧化硅催化的炔丙基胺与CO _2的羧基环化

通过仅使用二氧化硅作为催化剂，进行炔丙基胺与CO ₂的羧基环化反应，得到相应的2-恶唑烷酮。MCM-41是中孔二氧化硅，被发现是用于此目的的最有效的二氧化硅。此外，反应后，通过过滤回收MCM-41催化剂，并且可以在不失活的情况下重复使用十次以上。