Intermolecular hydrogen bonding controlled stereoselective photocycloaddition of vinyl ethers to 1-cyanonaphthalenes
作者:Hajime Maeda、Hiroki Takenaka、Kazuhiko Mizuno
DOI:10.1039/c6pp00281a
日期:2016.11
hydrogen bonding interactions to control the efficiency and stereochemistry, the 1,2-[2 + 2] photocycloaddition reactions of 1-cyanonaphthalene derivatives with vinyl ethers possessing hydroxy groups were examined. The photoreaction of 1-cyano-4-(hydroxymethyl)naphthalene (1a) with 2-hydroxyethyl vinyl ether (2a) at room temperature was found to produce cycloadducts, endo-3aa and exo-3aa, in a non-stereoselective
为了开发使用分子间氢键相互作用来控制效率和立体化学的光反应,研究了1-氰基萘衍生物与具有羟基的乙烯基醚的1,2- [2 + 2]光环加成反应。发现1-氰基-4-(羟甲基)萘(1a)与2-羟乙基乙烯基醚(2a)在室温下的光反应以非立体选择性方式产生环加合物,内-3aa和外-3aa(56) :44)。但是,这种在−40°C下的光反应显示出高的内选择性(81:19)。在1a与乙基乙烯基醚(2b)的反应中,高在室温和-40℃下均观察到内选择性。[2 + 2]光环加成过程中的内在选择性归因于基态和激发态下反应伙伴之间的分子间氢键相互作用。支持此结论的证据来自VT NMR和荧光猝灭实验的结果,以及氘代底物的光反应。