The experimental and theoretical studies of the reactions of 5,5-dimethylcyclohexane-1,3-dione (dimedone) with trimethyl- and triethyl orthoformates under various conditions were carried out. It was demonstrated that in the absence of activators the reactions of substrate with ortho esters proceed exclusively as C-C coupling, and in the presence of Brønsted (H2SO4) or Lewis (BF3·Et2O) acids the formation of both C-C and C-O coupling products is observed. The energy consumptions of all reactions in accordance with proposed mechanisms were estimated using quantum chemical calculations by the B3LYP/6-311++G(d,p) method in terms of PCM/MeCN.
对5,5-二
甲基环己烷-1,3-二酮(
二甲酮)与
原甲酸三甲酯和
原甲酸三乙酯在各种条件下的反应进行了实验和理论研究。结果表明,在没有活化剂的情况下,底物与原酯的反应仅以C-C偶联的方式进行,而在有布伦斯特(H2SO4)或路易斯(
BF3·Et2O)酸的情况下,观察到C-C和C-O偶联产物的形成。根据所提出的机制,使用B3LYP/6-311++G(d,p)方法,以PCM/MeCN为条件,通过量子
化学计算对所有反应的能量消耗进行了估算。