自由基环化制备β-内酰胺的理论研究  

Theoretical Study on Radical Cyclizations for Preparation of β-Lactams

作　　者：孟祥明[1] 俞一赟[1] 石景[1] 傅尧[1] 

机构地区：[1]中国科学技术大学化学系

出　　处：《有机化学》2008年第4期685-692,共8页Chinese Journal of Organic Chemistry

基　　金：国家自然科学基金(No.20602034);安徽省自然科学基金(No.070416237)资助项目.

摘　　要：使用密度泛函方法在UB3LYP/6-311++G(3df,2p)水平上对自由基环化合成β-内酰胺的四种反应途径进行理论研究.结合Marcus理论对影响反应的热力学及动力学因素进行分析,发现氨基甲酰基自由基4-exo环合反应是理想的动力学控制过程;酰胺自由基的4-exo环合反应与5-endo环合反应相比是动力学有利的转化过程;单取代的酰胺烷基自由基的4-exo环合反应是一类动力学和热力学都较为不利的反应;羰基自由基加成亚胺N=C双键的4-exo环合反应与5-endo环合反应相比动力学不利而热力学有利.The preparation of β-lactams through four different radical cyclization reactions was studied by density functional theory calculations at the UB3LYP/6-311 ＋＋G（3df, 2p） level. Thermodynamics and kinetics of these radical cyclizations were analyzed using the Marcus theory. The calculated results showed that the 4-exo cyclization of carbamoyl radical was an ideal kinetic-control process. The 4-exo cyclization of carbamoylalkyl radical was predicted to be kinetically competitive with the 5-endo process. The 4-exo cyclization of amido radical was less favorable both kinetically and thermodynamically. Finally, the 4-exo ring closure of an acyl radical onto an imine acceptor was thermodynamically competitive with the 5-endo process but less favorable kinetically.

关 键 词：Β-内酰胺 自由基环化反应 密度泛函方法 Marcus理论 

分 类 号：O621.3[理学—有机化学]