Scope and selectivity in palladium-catalyzed directed C–H bond halogenation reactions
作者:Dipannita Kalyani、Allison R. Dick、Waseem Q. Anani、Melanie S. Sanford
DOI:10.1016/j.tet.2006.06.075
日期:2006.12
Palladium-catalyzed ligand directed C–H activation/halogenation reactions have been extensively explored. Both the nature of the directing group and the substitution pattern on the arene ring of the substrate lead to different reactivity profiles, and often different and complementary products, in the presence and absence of the catalyst.
Copper-catalyzed aromatic C–H bond halogenation with lithium halides under aerobic conditions
作者:Song Mo、Yamin Zhu、Zengming Shen
DOI:10.1039/c3ob40185e
日期:——
A concise and practical Cu-catalyzed protocol for the preparation of chloro- and bromoarenes via C–H bond activation has been developed. The advantages of this strategy are the employment of cheap Cu(NO3)2·3H2O, LiX and O2, and its compatibility with both electron-donating and electron-withdrawing substituents on aryl rings.
Copper-mediated C–H cyanation of (hetero)arenes with ethyl (ethoxymethylene)cyanoacetate as a cyanating agent
作者:Chaorong Qi、Xiaohan Hu、Huanfeng Jiang
DOI:10.1039/c7cc03384b
日期:——
A copper-mediated direct C–H cyanation reaction of (hetero)arenes with ethyl (ethoxymethylene)cyanoacetate as a safe cyanating agent has been developed.
Regioselectivity-Switchable Hydroarylation of Styrenes
作者:Ke Gao、Naohiko Yoshikai
DOI:10.1021/ja108809u
日期:2011.1.26
Cobalt-phosphine and cobalt-carbene catalysts have been developed for the hydroarylation of styrenes via chelation-assisted C-H bond activation, to afford branched and linear addition products, respectively, in a highly regioselective fashion. Deuterium-labeling experiments suggested a mechanism involving reversible C-H bond cleavage and olefin insertion steps and reductive elimination as the rate-
Homoleptic lithium tri‐ and tetraalkyl zincates were reacted with a set of bromopyridines. Efficient and chemoselective bromine–metal exchanges were realized at roomtemperature with a substoichiometric amount of nBu4ZnLi2⋅TMEDA reagent (1/3 equiv; TMEDA=N,N,N′,N′‐tetramethylethylenediamine). This reactivity contrasted with that of tBu4ZnLi2⋅TMEDA, which was inefficient below one equivalent. DFT calculations