24434-84-2Relevant articles and documents
On-Demand Generation and Use in Continuous Synthesis of the Ambiphilic Nitrogen Source Chloramine
Danahy, Kelley E.,Styduhar, Evan D.,Fodness, Aria M.,Heckman, Laurel M.,Jamison, Timothy F.
, p. 8392 - 8395 (2020)
Herein, we demonstrate the on-demand synthesis of chloramine from aqueous ammonia and sodium hypochlorite solutions, and its subsequent utilization as an ambiphilic nitrogen source in continuous-flow synthesis. Despite its advantages in cost and atom economy, chloramine has not seen widespread use in batch synthesis due to its unstable and hazardous nature. Continuous-flow chemistry, however, provides an excellent platform for generating and handling chloramine in a safe, reliable, and inexpensive manner. Unsaturated aldehydes are converted to valuable aziridines and nitriles, and thioethers are converted to sulfoxides, in moderate to good yields and exceedingly short reaction times. In this telescoped process, chloramine is generated in situ and immediately used, providing safe and efficient conditions for reaction scale-up while mitigating the issue of its decomposition over time.
Visible-Light-Promoted Metal-Free Synthesis of (Hetero)Aromatic Nitriles from C(sp3)?H Bonds**
Murugesan, Kathiravan,Donabauer, Karsten,K?nig, Burkhard
supporting information, p. 2439 - 2445 (2020/12/07)
The metal-free activation of C(sp3)?H bonds to value-added products is of paramount importance in organic synthesis. We report the use of the commercially available organic dye 2,4,6-triphenylpyrylium tetrafluoroborate (TPP) for the conversion of methylarenes to the corresponding aryl nitriles via a photocatalytic process. Applying this methodology, a variety of cyanobenzenes have been synthesized in good to excellent yield under metal- and cyanide-free conditions. We demonstrate the scope of the method with over 50 examples including late-stage functionalization of drug molecules (celecoxib) and complex structures such as l-menthol, amino acids, and cholesterol derivatives. Furthermore, the presented synthetic protocol is applicable for gram-scale reactions. In addition to methylarenes, selected examples for the cyanation of aldehydes, alcohols and oximes are demonstrated as well. Detailed mechanistic investigations have been carried out using time-resolved luminescence quenching studies, control experiments, and NMR spectroscopy as well as kinetic studies, all supporting the proposed catalytic cycle.
Difluorocarbene-Based Cyanation of Aryl Iodides
Cao, Yu-Cai,Du, Ruo-Bing,Fu, Zhi-Hong,Guo, Yu,Lin, Jin-Hong,Xiao, Ji-Chang,Xiao, Xuan,Yao, Xu,Zhang, Yin-Xiang,Zheng, Xing
supporting information, p. 713 - 717 (2020/04/08)
A large number of efficient cyanation methods have been developed because of the wide range of applications of nitriles, but conventional methods usually suffer from the need for a toxic cyanation reagent. Although difluorocarbene chemistry has received increasing attention, the use of difluorocarbene as a sources of the nitrile carbon for nitrile groups remains largely unexplored. We describe a difluorocarbene-based cyanation of aryl iodides promoted by a cheap copper source, Cu(NO 3) 2 ·2.5H 2 O, under an air atmosphere. Ph 3 P + CF 2 CO 2-, an easily available and shelf-stable difluorocarbene reagent, and NaNH 2 are used as the carbon source and the nitrogen source for the nitrile group, respectively. The cyanation protocol is attractive because no toxic reagent is used and performing the reactions under an air atmosphere is operationally convenient.