EaStCHEM, School of Chemistry, University of Edinburgh, Joseph Black Building, The King's Buildings, West Mains Road, Edinburgh, EH9 3JJ, United Kingdom.
J Am Chem Soc. 2013 Jul 24;135(29):10829-36. doi: 10.1021/ja404867k. Epub 2013 Jul 15.
Achieving site-selective, switchable C-H functionalizations of substrates that contain several different types of reactive C-H bonds is an attractive objective to enable the generation of different products from the same starting materials. Herein, we demonstrate the divergent C-H functionalization of unsymmetrical 2-aryl cyclic 1,3-dicarbonyl compounds that contain two distinct, nonadjacent sites for initial C-H functionalization, where product selectivity is achieved through catalyst control. By use of a palladium-N-heterocyclic carbene complex as the precatalyst, these substrates undergo oxidative annulation with alkynes to provide spiroindenes exclusively. In contrast, a ruthenium-based catalyst system gives benzopyrans as the major products. Examples of divergent, oxidative C-H alkenylations of the same substrates are also provided.
实现含有多种反应性 C-H 键的底物的位点选择性、可切换的 C-H 官能化，是从同一起始原料生成不同产物的有吸引力的目标。在此，我们展示了含有两个不同、非相邻初始 C-H 官能化位点的不对称 2-芳基环状 1,3-二羰基化合物的发散 C-H 官能化，其中通过催化剂控制实现产物选择性。使用钯-N-杂环卡宾配合物作为前催化剂，这些底物与炔烃进行氧化环加成，仅提供螺茚满。相比之下，基于钌的催化剂体系得到苯并吡喃作为主要产物。还提供了同一底物的发散、氧化 C-H 烯基化的实例。
