Diastereotopic Group Selection in Hydroxy‐Directed Intramolecular CH Alkenylation of Indole under Oxidative Palladium(II) Catalysis
作者:Sandeep R. Kandukuri、Lin‐Yu Jiao、Axel B. Machotta、Martin Oestreich
DOI:10.1002/adsc.201301108
日期:2014.5.5
intermolecular hydroxy‐directed CH bond alkenylations. No asymmetric induction was obtained with chiral ligands, mono‐N‐protected amino acids (MPAAs) in particular. Conversely, the cyclization of indole‐derived precursors was substantially more efficient, and installation of a substituent in the benzylic position rendered these intramolecular CH bond alkenylations diastereoselective. The diastereotopic
报道了涉及CH键烯基化的基团选择性钯(II)催化的闭环反应。环化前体包含拴在芳烃或吲哚上的前手性双(均烯丙基)醇单元。在这些底物上的高苄基羟基被定位为在环化事件发生之前在邻位选择性CH键活化中充当引导基团。即使采用已证明在分子间羟基定向的CH键烯基化反应中有效的方案,芳烃衍生的前体反应也较差。手性配体mono- N未获得不对称诱导受保护的氨基酸(MPAA),尤其是。相反,吲哚衍生的前体的环化效率更高,并且在苄基位置上安装取代基使得这些分子内CH键烯基化反应具有非对映选择性。非对映异构基团的选择较高,非对映异构体比率为dr = 91:9至94:6。