手性BINOL自组装体的构筑与催化不对称反应研究

The development of highly efficient and selective chiral catalysts with broad scopes and practical economics is a widely concerned scientific problem in the area of asymmetric catalysis. By mimicking natural enzymes and combining the supramolecular self-assembly and the asymmetric catalysis, this project intends to focus on the design and construction of structurally novel chiral supramolecular catalysts based on the widely used BINOL ligands. Pyridyl will be introduced onto BINOL as a kind of easily tunable functional groups to furnish the pyridyl-derived BINOLs, which will then coordinate with metalloporphyrins to adjust steric hindrance and electronic properties of BINOL. A supramolecular chiral catalyst library with noticeable structural diversity can be built when a variety of metalloporphyrins with different substituents are used. The pyridyls on the BINOL derivatives will be further utilized to coordinate with the metal ions in a cyclic triporphyrin complex that has been previously reported by our research group, to form the supramolecular chiral catalysts, of which the BINOL catalytic active site is located in a narrow cavity of the soluble triporphyrin nanoring. In addition, a series of discrete chiral BINOL self-assemblies containing two or more chiral centers and having a large two- or three-dimensional cavity will be prepared via the coordination-driven self-assembly strategy. Furthermore, these prepared supramolecular chiral catalysts or chiral self-assemblies will be applied to chiral recognition of small organic molecules and to catalyzing asymmetric addition reactions of carbonyls or imines. The catalytic activities, the catalytic mechanism, the influence of supramolecular assembly process on asymmetric catalysis, and the synergetic mechanism of multi-chiral sites will be systematically investigated. This project is expected to provide a few novel methods for the construction of chiral functional self-assemblies as well as new strategies on the design of highly efficient chiral catalysts.

设计和寻求具有不断改进的通用性、活性和选择性的新型手性催化剂始终是不对称催化领域的焦点科学问题。本项目拟将超分子自组装与不对称催化相结合，在被广泛应用的BINOL类手性配体中引入吡啶基等易于调控的信息特征，利用吡啶与金属卟啉的轴向配位作用调控手性配体的立体和电子性质，改变卟啉的衍生基团获得结构多样的超分子手性催化剂库；利用我们此前所报道的三卟啉大环主体中的金属离子与手性BINOL衍生的吡啶进行配位组装，形成BINOL催化活性中心位于可溶性三卟啉狭小空腔内部的超分子手性催化剂；通过配位驱动自组装，制备一系列含有多个手性中心、且具有二维或三维空腔的离散型手性BINOL自组装体。将上述手性组装体应用于手性识别和催化羰基、亚胺等的不对称加成反应，系统考察其催化性能，探索超分子组装过程与催化反应及多手性位点的协同作用机制，为新型手性功能组装体的构筑提供新方法，并为高效手性催化剂的设计探索新思路。

项目围绕新型手性自组装体的构筑、高效超分子手性催化剂的设计制备与应用等关键科学问题，通过在BINOL等手性配体中引入吡啶基等易于调控的信息特征，利用配位自组装、主客体作用等构筑了一系列新型的手性自组装体和超分子手性催化剂。制备了一系列吡啶等修饰的新型手性BINOL衍生物；通过金属配位驱动自组装制备了一系列含有多个手性中心的离散型手性BINOL自组装体；通过金属卟啉与吡啶的轴向配位组装构筑了一系列可调控的手性组装体和结构多样的超分子手性催化剂库；通过亚胺键的形成反应组装制备了一种新型的手性BINOL纳米笼。并将上述手性BINOL衍生物和组装体成功地应用于对手性胺、手性醇、手性氨基醇的对映选择性识别和催化不对称Michael加成、环加成等不对称反应，实现了不对称催化反应的超分子调控，调控后催化反应的对映选择性得到了明显提升。项目所取得的成果为手性识别新体系的构建和高效超分子手性催化剂的设计、制备与应用提供了一些新思路和新范例，为超分子化学与不对称催化的交叉渗透提供了有意义的实验依据和理论支持。