Cycloaddition Reactions of Active Cyclic Frustrated Lewis Pairs

我们最近首次合成了活性挫折五元和六元环磷/硼烷刘易斯对（P/B FLPs），并表明它们与有机π-试剂发生了许多环加成反应。本项目应阐明这些FLP环加成及其随后经常观察到的Alder-Rickert类似环还原的规则，以便为开发这些环加成/环还原序列的特定化学提供坚实的基础。这将包括两性离子异降冰片烯和-双环[2.2.2]辛烷的典型化学反应，以及由烯烃交换反应获得的光学活性环状FLPs的合成，以及它们作为不对称加氢的活性无金属催化剂的利用。我们计划了环状FLPs在磷-斯托克化学合成循环中的应用。我们的新环状五元和六元环状FLPs的不饱和二聚体将用于拓扑化学环闭合反应，这可能首次为FLP冠和FLP笼化合物开辟可行的入口。两者都可能对小分子活化感兴趣。

We have recently developed syntheses of first examples of active frustrated five- and six-membered cyclic phosphane/borane Lewis pairs (P/B FLPs) and shown that they undergo a number of cycloaddition reactions with organic π-reagents. The rules, which govern such FLP cycloadditions and their often subsequently observed Alder-Rickert analogous cycloreversions, shall be clarified by this project in order to provide a sound basis to develop the specific chemistry of these cycloaddition/cycloreversion sequences. This will include the typical chemistry of the zwitterionic hetero-norbornenes and -bicyclo[2.2.2]octanes as well as the synthesis of optically active cyclic FLPs, obtained by alkene exchange reactions, and their utilization as active metal-free catalysts for asymmetric hydrogenation. We have planned applications of cyclic FLPs in synthetic cycles in phospha-Stork chemistry. Unsaturated dimers of our new cyclic five- and six-membered cyclic FLPs will be used for topochemical ring closure reactions, which for the first time might open viable entries to FLP crown and FLP cage compounds. Both are probably of interest for small molecule activation.