Structure and Reactivity of Aromatic Radical Cations Generated by FeCl<sub>3</sub>
作者:Takahiro Horibe、Shuhei Ohmura、Kazuaki Ishihara
DOI:10.1021/jacs.8b12827
日期:2019.2.6
and characterization of an aromatic radicalcation generated by FeCl3. X-ray crystallographic analysis and kinetic studies reveal the mechanism of the generation of aromatic radicalcation. In the solid state, a tight ion-pair of a radicalcation with FeCl4- is observed. Leveraging the efficient generation of the radical cation-FeCl4- ion pair, we explore a radical cation-induced cycloaddition of trans-anethole
organophotoredox catalysts that operate under irradiation with green light have been developed. These catalysts present high excited-state reduction potentials (E0′(C∗/C−) = +1.79–1.94 V vs SCE). They are able to efficiently activate dienophiles under green or blue light irradiation afforded the targeted radicalcation Diels-Alder cycloadducts in good yields. The present thioxanthylium-based catalysts provide
已经开发了在绿光照射下操作的基于硫杂蒽鎓的有机光还原催化剂。这些催化剂具有较高的激发态还原电位(E 0 '(C ∗ / C -)= + 1.79–1.94 V vs SCE)。它们能够在绿光或蓝光辐射下有效活化亲二烯体,从而以高收率获得了目标自由基阳离子Diels-Alder环加合物。本发明的基于噻吨鎓的催化剂提供了新的绿光驱动的光氧化还原催化体系。
Electronically Mismatched Cycloaddition Reactions via First-Row Transition Metal, Iron(III)–Polypyridyl Complex
作者:Jung Ha Shin、Eun Young Seong、Hyeon Jin Mun、Yu Jeong Jang、Eun Joo Kang
DOI:10.1021/acs.orglett.8b02541
日期:2018.9.21
one-electron oxidant, producing radicalcations from olefins and promoting the efficient radicalcation [2 + 2] and [2 + 4] cycloaddition reactions. Subsequent chain propagation afforded trisubstituted cyclobutane or cyclohexene derivatives, and this facile route enables the replacement of rare metals with sustainable, green, and inexpensive iron in radicalcationcycloadditions.
Visible-Light-Irradiated Graphitic Carbon Nitride Photocatalyzed Diels-Alder Reactions with Dioxygen as Sustainable Mediator for Photoinduced Electrons
作者:Yubao Zhao、Markus Antonietti
DOI:10.1002/anie.201703438
日期:2017.8.1
photoredox system. Moreover, the reactionintermediate vinylcyclobutane is captured and monitored during the reaction, serving as a direct evidence for the proposed reaction mechanism. The cycloaddition process is thereby determined to be the combination of direct [4+2] cycloaddition and [2+2] cycloaddition followed by photocatalytic rearrangement of the vinylcyclobutane intermediate.
石墨碳氮化物(g-C 3 N 4)在可见光辐射和有氧条件下,与富电子烯烃的光催化Diels-Alder(D-A)反应得以实现。这种异质的光氧化还原反应系统非常高效,模型反应的表观量子产率达到了47%的显着值。双氧作为电子介体起着至关重要的作用,这与先前有关均相Ru II的报道不同复杂的光氧化还原系统。此外,在反应过程中捕获并监测了反应中间体乙烯基环丁烷,为提出的反应机理提供了直接证据。从而将环加成过程确定为直接的[4 + 2]环加成和[2 + 2]环加成,然后进行乙烯基环丁烷中间体的光催化重排的组合。
Aromatic “Redox Tag”-assisted Diels–Alder reactions by electrocatalysis