Škoch Karel, Daniliuc Constantin G, Müller Marcel, Grimme Stefan, Kehr Gerald, Erker Gerhard
Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149, Münster, Germany.
Current address: Institute of Inorganic Chemistry of the, Czech Academy of Sciences, Husinec, 250 68, Husinec-Řež (Czech Republic.
Chemistry. 2022 Apr 6;28(20):e202200248. doi: 10.1002/chem.202200248. Epub 2022 Feb 22.
The P-stereogenic bis(phosphanes) 7 and 9, featuring pairs of P(Mes)-ethynyl or vinyl substituents at the dimethyl xanthene backbone show rather low barriers of stereochemical inversion at phosphorus. π-Conjugative effects are probably causing these low inversion barriers. Compound 7 reacted with B(C F ) to form the nine-membered heterocyclic product 10, featuring a [P]-C≡C-B(C F ) substituent. Compound 7 was converted to the bis[P(Mes)vinyl] xanthene derivative 9, which gave the zwitterionic P(H)(Mes)-CH=CH-B(C F ) containing product 16 upon treatment with B(C F ) . Thermally induced epimerization barriers at phosphorus of ca. 20 to 27 kcal mol were calculated by DFT for the alkenyl- and alkynyl-P derived systems 6 to 9, 15 and 16 and experimentally determined for the examples 7 and 16.
具有在二甲基氧杂蒽骨架上成对的P（Mes）-乙炔基或乙烯基取代基的P-立体中心双（膦）7和9在磷上显示出相当低的立体化学反转势垒。π共轭效应可能导致了这些低反转势垒。化合物7与B（CF）反应形成具有[P]-C≡C-B（CF）取代基的九元杂环产物10。化合物7被转化为双[P（Mes）乙烯基]氧杂蒽衍生物9，其在用B（CF）处理时得到含两性离子P（H）（Mes）-CH=CH-B（CF）的产物16。通过DFT计算了烯基和炔基-P衍生体系6至9、15和16在磷上的热诱导差向异构化势垒约为20至27 kcal mol，并通过实验测定了实例7和16的势垒。
