催化氧烯丙基钯环加成反应研究

氧烯丙基钯是一类非常重要的活性中间体，基于它的环加成反应已经研究了近三十年，然而直到近期才有所突破。该领域发展缓慢的主要原因在于缺少足够的手段对氧烯丙基钯的化学反应进行精准调控。本项目基于这些难点与挑战开展如下工作：我们计划引入路易斯酸调控其活性实现C-C还原消除的（3+2）和（4+3）环加成反应。我们还计划通过取代基团和配体调控实现氧烯丙基钯物种的极性反转，从而实现电子需求反转的环加成反应。最后，我们计划将弱相互作用力引入氧烯丙基钯，开发新型的氢键给体配体，对氧烯丙基钯的立体化学进行调控，实现首例不对称氧烯丙基钯环加成反应。

Palladium-oxyally is an important reactive species, which has drawn research interests on its cycloaddition reaction for more than thirty years. However, it was not until very recently that a big breakthrough was achieved. The biggest challenge in developing palladium-oxyally cycloaddition reaction is how to control the chemoselectivities, including regioselectivity, diastereoselectivity and enantioselectivity. In this project, we aim to achieve regioselective (3+2) and (4+3) cycloaddition reactions featuring C-C reductive elimination by employing a Lewis acid to tune the reaction pathway of palladium-oxyally. We also plan to achieve the umpolung of palladium-oxyally by the cooperative effect of substitution group and ligand, which enables the first inverse-electron-demand cycloaddition of palladium-oxyally. Finally, we plan to introduce weak non-covalent interactions into palladium-oxyally. Based on this strategy, a new type of ligands containing H-bond donor moiety was designed, which enables the first asymmetric palladium-oxyally cycloaddition reaction.