prepared and tested as simple catalysts of oxidations with hydrogen peroxide, using sulfoxidation as a model reaction. Their catalyticefficiency strongly depends on the type of substituent and is remarkable for derivatives with an electron-withdrawing group, showing reactivity comparable to that of flaviniumsalts which are the prominent organocatalysts for oxygenations. Because of their high stability
制备了一系列的单取代的嘧啶鎓和吡嗪鎓三氟甲磺酸酯和3,5-二取代的吡啶鎓三氟甲磺酸酯,并使用硫氧化作为模型反应,对过氧化氢的简单氧化催化剂进行了测试。它们的催化效率在很大程度上取决于取代基的类型,并且对于具有吸电子基团的衍生物而言是显着的,其反应性与黄酮盐相当,后者是氧合作用的主要有机催化剂。由于它们的高稳定性和良好的可及性,4-(三氟甲基)嘧啶鎓和3,5-二硝基吡啶鎓三氟甲磺酸盐是选择的催化剂,并显示出催化脂肪族和芳香族硫化物氧化为亚砜的作用,定量转化率高,制备产率高,并且具有优异的性能。化学选择性。K R +值(p K R + <5)和较小的负还原电位(E red > -0.5 V)。在催化氧化过程中原位形成的过氧化氢加合物充当底物氧化剂。通过在B3LYP / 6-311 ++ g(d,p)水平上的计算获得的从这些杂环氢过氧化物到硫代苯甲醚的转移的吉布斯自由能表明,它们是比烷基氢过氧化
Trapping of Pyrid-2-ylidenes by [Ru<sub>3</sub>(CO)<sub>12</sub>]: Orthometalated Pyrid-2-ylidenes in Triruthenium Clusters
作者:Javier A. Cabeza、Ignacio del Río、Enrique Pérez-Carreño、M. Gabriela Sánchez-Vega、Digna Vázquez-García
DOI:10.1021/om100574j
日期:2010.10.25
N-heterocyclic carbenes having only one N atom (NHC1N-R6 carbenes) can be easily prepared by simple deprotonation of readily available N-methylpyridinium-type cations with K[N(SiMe3)2]. They have been trapped in solution with [Ru3(CO)12] to give novel triruthenium clusters that contain orthometalated NHC1N-R6 carbeneligands in a face-capping coordination mode. Four NHC1N-R6-derived compounds of general
Concurrent one- and two-electron processes in electrophile/nucleophile interactions of organometallic ion pairs
作者:R. E. Lehmann、T. M. Bockman、J. K. Kochi
DOI:10.1021/ja00157a076
日期:1990.1
Interaction electrophyle/nucleophile entre CpMo(CO) 3 − et (η 5 -L)Fe(CO) 3 + , L=cyclohexadienyl, cycloheptadienyl, pentadienyl, hexadienyl
亲电体/亲核体相互作用 entre CpMo(CO) 3 − et (η 5 -L)Fe(CO) 3 + , L=环己二烯基、环庚二烯基、戊二烯基、己二烯基
Heteroaromatic compounds having two-photon absorption activity
申请人:——
公开号:US20030118916A1
公开(公告)日:2003-06-26
The present invention relates to new heteroaromatic compounds having two-photon absorption activity. According to the invention, said compounds are suitable for use as optical power limiting agents via two-photon absorption or for use as imaging agents with two-photon absorbing activity for application in two-photon laser scanning confocal fluorescence microscopy. Compositions including said compounds and intermediates for their preparations are also within the scope of the present invention.
Dearomatization of Heteroarenium Salts with ArBpin Reagents. Application to the Total Synthesis of a Nuphar Alkaloid
作者:Donovan J. Robinson、Kacey G. Ortiz、Nathan P. O’Hare、Rashad R. Karimov
DOI:10.1021/acs.orglett.2c00976
日期:2022.5.20
Rhodium-catalyzed enantioselective addition of aryl and heteroaryl boron pinacol esters to pyridinium and quinolinium salts is developed for the synthesis of enantioenrichred dihydroheteroarenes. The methodology has enabled the synthesis of 2-heteroaryl-substituted dihydropyridines in high yield and ee, which provided efficient synthetic access to a nuphar alkaloid.
开发了铑催化的芳基和杂芳基硼频哪醇酯与吡啶鎓和喹啉鎓盐的对映选择性加成,用于合成对映富集的二氢杂芳烃。该方法能够以高产率和 ee 合成 2-杂芳基取代的二氢吡啶,这为获得单麻生物碱提供了有效的合成途径。