Electrocatalytic Diazidation of Alkenes
Electrocatalytic Diazidation of Alkenes
复制标题
烯烃的电催化二叠氮化
DOI：
10.1016/j.trechm.2019.10.005
复制
发表时间：
2020
影响因子：
15.7
通讯作者：
Lin, Song
中科院分区：
文献类型：
--
作者：
Novaes, Luiz F.T.;Lin, Song
通过C=C双键添加两个官能团的烯烃的双官能化可以采用亲核、亲电或自由基机理。我们课题组开发的电催化重氮化反应经历了由氧化还原活性的过渡金属催化剂介导的自由基途径，对烯烃的结构和电子性质相对不敏感。循环伏安和光谱数据支持如下所示的建议的催化循环。MnII催化剂首先参与与叠氮阴离子的配体交换，生成[MnII]-N3络合物(A)。该中间体在碳阳极上被氧化成相应的MnIII物种(B)，该物种随后将叠氮基转移到烯烃(I)上，生成自由基中间体II(C)。催化循环重复进行，[MnIII]-N3还负责将第二当量叠氮基传递到中间体II以完成重氮化反应。[MnIII]-N3络合物的阳极生成是该机理的一个关键特征，因为这种催化物种在反应中起着几个关键作用。[MnIII]-N3可以在比自由基叠氮基(N3·)更低的电势下生成，并且它保留了诱导烯烃π键均裂的自由基性质。此外，碳心自由基II是一种瞬时自由基，可以发生二聚化和过氧化等各种副反应。然而，[MnIII]-N3有效地捕获II，以确保高的反应选择性。在电化学反应的还原方面，来自醋酸的质子在铂阴极表面还原生成氢气(D)。
The difunctionalization of alkenes, in which two functional groups are added across a C= C double bond, can adopt nucleophilic, electrophilic, or radical mechanisms. The electrocatalytic diazidation developed by our group undergoes a radical pathway mediated by a redox-active transitionmetal catalyst and is relatively insensitive to the structure and electronic property of the alkene. Cyclic voltammetry and spectrometry data support the proposed catalytic cycle shown below. The MnII catalyst first participates in ligand exchange with the azide anion to generate a [MnII]–N3 complex (A). This intermediate is oxidized on the carbon anode to the corresponding MnIII species (B), which subsequently transfers an azidyl group to the alkene (I) to generate radical intermediate II (C). The catalytic cycle is repeated and [MnIII]–N3 is also responsible for delivering the second equivalent of azidyl to intermediate II to complete diazidation. The anodic generation of the [MnIII]–N3 complex is a key feature of this mechanism, as this catalytic species plays several key roles in the reaction.[MnIII]–N3 can be produced at a lower potential than the free azidyl radical (N3•) and it preserves a radical nature that induces homolysis of the π bond of the alkene. In addition, carbon-centered radical II is a transient radical and can undergo various side reactions such as dimerization and overoxidation. However,[MnIII]–N3 captures II efficiently to ensure high reaction selectivity. On the reductive side of the electrochemical reaction, protons from acetic acid are reduced on the platinum cathode surface to generate hydrogen gas (D).
影响因子：
14.8
作者：
Fu, Niankai;Sauer, Gregory S.;Lin, Song
通讯作者：
Lin, Song
DOI：
10.1002/anie.201507550
发表时间：
2016-01-11
期刊：
Angewandte Chemie (International ed. in English)
影响因子：
--
作者：
Yuan YA;Lu DF;Chen YR;Xu H
通讯作者：
Xu H
影响因子：
12.9
作者：
Sauer, Gregory S.;Lin, Song
通讯作者：
Lin, Song