有机自由基通常是具有异常高反应性的短寿命中间体。从战略上讲,实现由有机自由基介导的合成有用的转化需要有效的引发和选择性终止事件。在这里,我们报告了一种新的催化策略,即双金属自由基氧化还原继电器,用于环氧化物向烯丙醇的区域和立体选择性重排。这种方法利用了 Ti 和 Co 配合物的丰富氧化还原化学,并将还原性环氧化物开环(引发)与氢原子转移(终止)相结合。至关重要的是,在影响关键的成键和断裂事件时,Ti 和 Co 催化剂彼此进行质子转移/电子转移以实现周转,从而构成真正协同的双催化系统。
Copper porphyrin-catalyzed cross dehydrogenative coupling of alkanes with carboxylic acids: Esterification and decarboxylation dual pathway
作者:Xiao-Yan Chen、Shuang Yang、Bao-Ping Ren、Lei Shi、Dong-Zi Lin、Hao Zhang、Hai-Yang Liu
DOI:10.1016/j.tet.2021.132377
日期:2021.9
A dual-functional copper porphyrin-catalyzed cross dehydrogenative coupling (CDC) of carboxylic acids with alkanes was reported firstly. The reaction gives allylic esters or alkylalkenes depending on the carboxylic acid substrates. Copper porphyrin catalyzed CDC method has the superiority of short reaction time, good functional group tolerance, base and solvent free, producing target products in an
Copper-catalyzed oxidative dehydrogenative functionalization of alkanes to allylic esters
作者:Rakesh Mondal、Gargi Chakraborty、Kaj M. van Vliet、Nicolaas P. van Leest、Bas de Bruin、Nanda D. Paul
DOI:10.1016/j.ica.2019.119190
日期:2020.1
efficient and solvent-free method for the one-pot synthesis of allylic esters via dehydrogenation of unactivated alkanes and subsequent oxidative cross coupling with different substituted carboxylic acids. A simple, well defined and air stable Cu(II)-complex, [Cu(MeTAA)], featuring a tetraaza-macrocyclic ligand (tetramethyltetraaza[14]annulene (MeTAA)) is used as the catalyst. A wide variety of substituted
Copper-Catalyzed Oxidative Dehydrogenative Carboxylation of Unactivated Alkanes to Allylic Esters via Alkenes
作者:Ba L. Tran、Matthias Driess、John F. Hartwig
DOI:10.1021/ja510093x
日期:2014.12.10
with various substituted benzoic acids to produce the corresponding allylic esters. Spectroscopic studies (EPR, UV–vis) revealed that the resting state of the catalyst is [(BPI)Cu(O2CPh)] (1-O2CPh), formed from [(BPI)Cu(PPh3)2], oxidant, and benzoic acid. Catalytic and stoichiometric reactions of 1-O2CPh with alkyl radicals and radical probes imply that C–H bondcleavage occurs by a tert-butoxy radical
Asymmetric Trasformation of Symmetrical Epoxides to Allylic Alcohols by Lithium (<i>S</i>)-2-(<i>N</i>,<i>N</i>-Disubstituted aminomethyl)pyrrolidide
作者:Masatoshi Asami
DOI:10.1246/bcsj.63.721
日期:1990.3
Enantioselective deprotonation of symmetrical epoxides was studied by using chiral lithium amide, prepared from (S)-2-(N,N-disubstituted aminomethyl)pyrrolidine and butyllithium. Chiral allylic alcohols were obtained with moderate to high enantiomeric excesses (ee’s) (41–92% ee) from several cyclic and acyclic epoxides employing lithium (S)-2-(1-pyrrolidinylmethyl)pyrrolidide in tetrahydrofuran (THF) in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU).
Hydrosulfonylation of Alkenes with Sulfonyl Chlorides under Visible Light Activation
作者:Sandrine M. Hell、Claudio F. Meyer、Antonio Misale、Jeroen B. I. Sap、Kirsten E. Christensen、Michael C. Willis、Andrés A. Trabanco、Véronique Gouverneur
DOI:10.1002/anie.202004070
日期:2020.7.6
Sulfonyl chlorides are inexpensive reactants extensively explored for functionalization, but never considered for radical hydrosulfonylation of alkenes. Herein, we report that tris(trimethylsilyl)silane is an ideal hydrogen atom donor enabling highly effective photoredox‐catalyzed hydrosulfonylation of electron‐deficient alkenes with sulfonyl chlorides. To increase the generality of this transformation