A novel protocol for the synthesis of α-aryl nitriles has been successfully achieved via a copper-catalyzed cyanation of N-tosylhydrazones employing thiocyanate as the source of cyanide. The features of this method include a convenient operation, readily available substrates, low-toxicity thiocyanate salts, and a broad substrate scope.
Ring-Opening of Indoles: An Unconventional Route for the Transformation of Indoles to 1<i>H</i>-Pyrazoles Using Lewis Acid
作者:Subhankar Panda、Nirmalya Pradhan、Debasis Manna
DOI:10.1021/acscombsci.8b00071
日期:2018.10.8
unusual transformation of indoles to pyrazoles via an aromatic ring-opening strategy has been developed. The salient feature of this strategy involves the C2–N1 bond opening and concomitant cyclization reaction of the C2═C3 bond of the indole moiety with the tosylhydrazone, which proceeds under transition-metal and ligand free conditions. This ring-opening functionalization of indoles provides a wide scope
Direct Synthesis of Propen-2-yl Sulfones through Cascade Reactions Using Calcium Carbide as an Alkyne Source
作者:Lei Gao、Zhenrong Liu、Xiaolong Ma、Zheng Li
DOI:10.1021/acs.orglett.0c01915
日期:2020.7.2
A simple method for the construction of propen-2-yl sulfones through cascadereactions of calcium carbide with arylsulfonylhydrazones using copper as a mediator is described. The salient features of this protocol are the use of readily available and easy-to-handle alkyne source, broad substrate scope, open-air condition, and simple operation procedure.
A Transition-Metal-Free and Base-Mediated Carbene Insertion into Sulfur-Sulfur and Selenium-Selenium Bonds: An Easy Access to Thio- and Selenoacetals
作者:Dhanarajan Arunprasath、Govindasamy Sekar
DOI:10.1002/adsc.201600855
日期:2017.2.20
A transition‐metal‐free and base‐mediated carbene insertion across sulfur‐sulfur and selenium‐selenium bonds has been developed by employing N‐tosylhydrazone as a stable and safe carbene precursor. The ylide formation from carbene followed by Stevens rearrangement are considered to be the key steps. This thiol and selenol‐free protocol delivers thioacetals and selenoacetals in good to excellent yields
Iron Porphyrin Catalyzed Insertion Reaction of <i>N</i>-Tosylhydrazone-Derived Carbenes into X–H (X = Si, Sn, Ge) Bonds
作者:En-Hui Wang、Yuan-Ji Ping、Zong-Rui Li、Hongling Qin、Zhen-Jiang Xu、Chi-Ming Che
DOI:10.1021/acs.orglett.8b01931
日期:2018.8.3
An efficient Fe(TPP)Cl catalyzed insertionreaction of in situ generated benzylic carbenes from N-tosylhydrazones into X–H (X = Si, Sn, Ge) was developed. Silanes bearing tertiary, secondary, and primary (3°, 2°, and 1°) Si–H bonds all reacted well to afford insertion products in moderate to high yields (up to 97%), and the reaction time could be significantly shortened to 1 h under microwave irradiation