烯烃化合物的不对称串联亲电加成–成环反应研究

烯烃双键接受亲电试剂进攻后所形成的活性中间体（氯、碘或溴鎓离子，碳正离子等）再接受分子内亲核基团的进攻从而成环是有机合成中最常用的构建官能团化的环状结构的策略之一。本项目旨在发展一系列基于此策略的不对称催化体系，并将侧重于不对称有机小分子催化体系的发展。鉴于现已发展的绝大部分成功的不对称体系都局限于使用亲电卤化试剂的卤环化反应形成相应的内酯和环醚类结构，本项目侧重于对目前鲜有报道的以碳原子为亲电中心的亲电试剂的应用，研究手性仲胺、手性硫脲、手性磷酸等有机小分子催化剂催化共轭不饱和羰基化合物、硝基烯烃、亚胺、三氟甲基化试剂等引发高亲电性官能化烯烃类化合物的不对称成环串联反应，立体选择性地构建含有多个连续手性中心的复杂环状化合物。本项目的成功实施将会更加丰富复杂环状结构的合成方法学，具有重要的理论意义和实际应用价值。

Cyclization proceeding through an intramolecular nucleophilic attack of the active intermediate (chloronium, iodonium, bromonium, carbocation, etc.) formed by a prior electrophilic attack of the alkene double bond is one of the most common strategies used to construct functionalized cyclic structures in organic synthesis. Based on this strategy, this project is aimed to develop asymmetric catalytic systems in this field, with an emphasis on asymmetric organocatalysis. In view that most successful asymmetric catalytic systems so far developed have been restricted to the halocyclization using electrophilic halogenation reagents to form corresponding halogen-containing lactones and cyclic ethers, this project would focus on the utilization of currently rarely reported electrophilic reagents containing an carbon atom as the electrophilic center. Research efforts would be directed towards the application of small organic molecule catalysts such as chiral secondary amines, chiral thioureas and phosphoric acids to catalyze the asymmetric cyclizations of electron-rich alkenes initiated by the attack of unsaturated conjugated carbonyls, nitroolefins, imines and electrophilic trifluoromethylation reagents, leading to the stereoselective construction of complex cycles with several adjoining chiral centers. The successful execution of this project would add to the methodology for constructing complex cyclic structures, and thus would have both theoretical significance and practical value.