卡宾与醚C—H键插入反应的理论研究(Ⅲ)CX_2(X=H,F,Cl)与甲乙醚C—H键插入反应  

Theoretical Studies on the C—H Bond Insertion Reaction of Carbenes with Ethers (Ⅲ) Insertion Reaction of CX_2(X=H, F, Cl) with Ethyl Methyl Ether

作　　者：冯大诚[1] 林启君[1] 马万勇[2] 王焕杰[1] 

机构地区：[1]山东大学化学学院,济南250100 [2]山东轻工业学院化工系,济南250100

出　　处：《高等学校化学学报》2000年第11期1708-1712,共5页Chemical Journal of Chinese Universities

基　　金：教育部博士学科点基金;山东省自然科学基金! (批准号 :Y98B0 90 2 8)资助

摘　　要：用量子化学从头计算方法在 MP2 / 6-31 G( d)水平上研究了 CX2 ( X=H,F,Cl)与甲乙醚的 C— H键插入反应 .在甲乙醚的 3个不同的 C— H键 (即甲基中α -C— H键 ,乙基中α-C— H键和β-C— H键 )上 ,反应势垒分别为 1 2 3.8,32 .5,1 57.3k J/ mol( X=Cl)和 2 54.3,1 30 .0 ,30 4 .2 k J/ mol( X=F) .亚甲基与毗邻氧原子的各 C— H键插入反应没有势垒 ,与乙基中 β-C— H键插入势垒仅 3.4 k J/ mol.甲乙醚中乙基 α-C上的C— H键最有利于 CX2 的插入 ,甲基上的 C— H键次之 ,乙基 β-C上的又次之 .The insertion reactions between CX 2(X=H, F, Cl) and C—H bonds of ethyl methyl ether have been studied at MP2/6 31G(d) level by using ab initio calculation. The potential barriers for three different C—H bonds(namely α  C—H bonds in methyl group, α C—H bonds and β C—H bonds in ethyl group) are 123 8, 32 5, 157 3 kJ/mol(X=Cl) and 254 3, 130 0, 304 2 kJ/mol(X=F) respectively. No potential barrier is present in the insertion reaction between methylene and C—H bonds adjacent to the oxygen atom and the potential barrier for the insertion between methylene and β C—H bond in ethyl group is 3 4 kJ/mol. C—H bonds of α C in ethyl group of ethyl methyl ether are the most favourable to CX 2 insertion, C—H bonds in methyl group come next and β C—H bongs in ethyl group are the most unfavourable.

关 键 词：甲乙醚 卡宾 插入反应 从头计算 C-H键 

分 类 号：O613.71[理学—无机化学] O623.423[理学—化学]