We found that oxidation of cyclic ethers with the Ru porphyrin-heteroaromatic N-oxide system gave lactones or/and ring-opened oxidized products with regioselectivity. A relatively high kinetic isotope effect was observed in the ether oxidation, suggesting that the rate-determining step is the first hydrogen abstraction.
Fast Catalytic Hydroxylation of Hydrocarbons with Ruthenium Porphyrins
作者:Chuanqing Wang、Kirill V. Shalyaev、Marcella Bonchio、Tommaso Carofiglio、John T. Groves
DOI:10.1021/ic0520566
日期:2006.6.1
consistent with the formation of an active Ru(III) intermediate in situ by a one-electron reduction of the Ru(IV) porphyrin. EPR spectra characteristic of Ru(III) have been observed upon the reduction of Ru(IV)(TPFPP)Cl2 with a zinc amalgam. In the adamantane oxidation mediated with Ru(III)(TPFPP)(OEt), it was found that, during this process, the Ru(III) porphyrin was gradually converted to a dioxoRu(VI)
发现钌卟啉配合物,如四钌五氟苯基卟啉羰基钌(II)[Ru(II)(TPFPP)(CO)]是在2,6-二氯吡啶N-氧化物为氧化剂,温和条件下,烷烃羟基化的有效催化剂。 ,非酸性条件。对于金刚烷的羟基化,获得了高达14800的周转率(TO)和800 TO / min的速率。顺式十氢萘的羟基化作用仅提供了顺式九氢萘烷和顺式十氢萘9,10-二醇,因此排除了长寿命的自由基机理。在典型的催化氧合作用中,产物演化的动力学过程显示出一个初始的诱导期,随后是一个快速的,明显为零级的相,具有最大的速率和较高的效率。对于烷烃的羟基化,发现氘同位素效应(kH / kD)在4.2-6.4范围内。对对位取代的甲苯衍生物氧化的数据的Hammett处理显示出线性相关性,其中rho +值为-2.0。根据动力学和光谱学证据,排除了在催化过程中观察到的Ru(VI)(TPFPP)(O)2,Ru(II)(TPFPP)(CO)和Ru