Recently, inexpensive and readily available tBuOK has seen widespread use in transition-metal-free reactions. Herein, we report the use of tBuOK for S–S, S–Se, NN and CN bond formations, which significantly extends the scope of tBuOK in chemical synthesis. Compared with traditional methods, we have realized mild and general methods for disulfide, azobenzenes imine etc. synthesis.
A Concerted Transfer Hydrogenolysis: 1,3,2-Diazaphospholene-Catalyzed Hydrogenation of NN Bond with Ammonia-Borane
作者:Che Chang Chong、Hajime Hirao、Rei Kinjo
DOI:10.1002/anie.201400099
日期:2014.3.24
1,3,2‐diazaphospholenescatalyzemetal‐free transfer hydrogenation of a NN double bond using ammonia–borane under mild reaction conditions, thus allowing access to various hydrazine derivatives. Kinetic and computational studies revealed that the rate‐determining step involves simultaneous breakage of the BH and NH bonds of ammonia–borane. The reaction is therefore viewed as a concerted type of
Hydrogen peroxide based oxidation of hydrazines using HBr catalyst
作者:Jian Wang、Zichao Ma、Wanting Du、Liming Shao
DOI:10.1016/j.tet.2021.132546
日期:2021.12
Azo compounds (RN = NR′) are an important class of organic molecules that find wide application in organic synthesis. Herein, we report an efficient, practical and metal-free oxidation of hydrazines (RNH-NHR’) to azo compounds using 5 mol% HBr and hydrogen peroxide as terminal oxidant. This new method has been demonstrated by 40 examples with excellent yields. In addition, we showcased two examples
A highly efficient, metal-free, chemical oxidation of hydrazines has been implemented using environmentally friendly TCCA as oxidant. This benign protocol provides straightforward access to a wide range of azo compounds in THF in excellent yield. Altogether, 35 azo compounds were obtained in this way and scale-up preparations were performed. Additionally, a plausible mechanism was also proposed. Step-economical
Visible-light-promoted oxidative dehydrogenation of hydrazobenzenes and transfer hydrogenation of azobenzenes
作者:Xianya Wang、Xianjin Wang、Chungu Xia、Lipeng Wu
DOI:10.1039/c9gc01618j
日期:——
synthesize azo compounds from hydrazine derivatives. The use of visible-light with air as the oxidant makes this process sustainable and practical. Moreover, the visible-light-driven, photo-redox-catalyzed transfer hydrogenation of azobenzenes is compatible with a series of hydrogen donors such as phenyl hydrazine and cyclic amines. Compared with traditional (thermal/transition-metal) methods, our process avoids