3-亚甲基苯并吡喃-2,4-二酮与烯醇硅醚的Diels-Alder反应合成3,4- 二氢-2H,5H-吡喃并[3,2-c][1]苯并吡喃-5-酮衍生物

通过4-羟基香豆素与苯甲醛、甲醛和戊醛缩合产生的quinone methide与烯醇硅醚的Diels-Alder反应, 以较高产率合成了一系列含有硅氧基的3,4-二氢-2H,5H-吡喃并3,2-c]1]苯并吡喃-5-酮衍生物. 用X射线单晶衍射确定了其中5个化合物的空间构型. 利用密度泛函(DFT)方法计算反应物之间的前线分子轨道相互作用, 对反应的区域选择性进行了研究, 计算结果与实验值相符.

Synthesis of 3,4-Dihydro-2H,5H-pyrano[3,2-c][1]benzopyran-5-one Derivatives by Diels-Alder Reactions of 3-Methylenebenzopyran- 2,4-diones with Silyl Enol Ethers

Quinone methides, generated in situ from the reaction of 4-hydroxycoumarin with benzaldehyde, formaldehyde and pentanal, underwent the Diels-Alder reaction with silyl enol ethers to give a series of 3,4-dihydro-2H,5H-pyrano3,2-c]1]benzopyran derivatives in high yields. Steric configurations of five compounds were determined by X-ray diffraction experiments. The regioselectivity of the reactions was in-vestigated by frontier molecular orbital interactions between the reactants as calculated by a density func-tional theory (DFT) method, which well rationalized the observed data.