Cycloaddition Reactions of Active Cyclic Frustrated Lewis Pairs

我们最近开发了第一个例子的活性受挫的五元和六元环膦/硼烷刘易斯对（P/B FLP）的合成，并表明，他们进行了一些与有机π-试剂的环加成反应。本项目将阐明控制此类FLP环加成及其随后经常观察到的Alder-Rickert类似环逆转的规则，以便为开发这些环加成/环逆转序列的特定化学提供坚实的基础。这将包括典型的化学的两性离子的杂环戊二烯和双环[2.2.2]辛烷，以及合成的光学活性的环状FLP，通过烯烃交换反应得到的，和它们的利用作为活性的无金属催化剂的不对称氢化。我们已经计划将环状FLP应用于磷酸-Stork化学的合成循环中。我们新的环状五元和六元环状FLP的不饱和二聚体将用于拓扑化学闭环反应，这可能是第一次打开可行的条目FLP冠和FLP笼化合物。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.