磺化笼型介孔碳催化的1,1-二乙酸酯的选择性合成

Chemoselective Synthesis of 1,1-Diacetate from Aldehydes Catalyzed by Sulfonated Carbon Nanocage

以磺化的笼型介孔碳为催化剂温和、高效、高选择性地合成了缩羰基二乙酸酯．在室温和无溶剂条件下，用磺化的笼型介孔碳作催化剂使醛类化合物与乙酸酐之间在5—12min内反应生成1，1-二乙酸酯，产率高达89％-98％．在相同条件下酮类化合物不会发生此反应．反应后催化剂经过简单的处理即可回收利用，回收利用7次活性无明显降低．

Acetals are one of the most useful carbonyl protecting groups because of their stability under both neutral and basic media. In addition, acetals can be converted to a variety of other functional groups. Thus, to find a green synthesis method of acetals, the sulfonated carbon nanocage（S-CKT） as a reusable solid acid catalyst was applied to the reaction of aldehydes with acetic anhydride. As a result, a mild and efficient method was developed for the chemoselective preparation of 1,1-diacetates（acylals） from the mixture of alde- hydes （2 mmol） and acetic anhydride （5 mmol） catalyzed by S-CKT（30 rag） under room temperature and sol- vent-free conditions. The reaction takes a shorter time （5--12 rain） and gives good to excellent yield （89%- 98% ）. While it is found that ketone doesn＇t react with acetic anhydride to yield corresponding product under the same conditions. The catalyst was recycled seven times without a distinct loss of activity by simple filtration and washing