Oxidation of alkynes using ammonium persulfate and diphenyl diselenide as catalyst in aqueous media leads to 1,2-unprotected dicarbonyl derivatives or to hemiacetals starting from terminal alkynes.
S. Santoro, B. Battistelli, B. Gjoka, C.-w. S. Si, L. Testaferri, M. Tiecco, C. Santi, Synlett, 2010, 1402-1406.
An environmentally benign protocol for the iodination of activated aromatics, such as phenols, anilines, and hydroxycoumarins, using inexpensive commercially available potassium iodide and ammonium peroxodisulfate in aqueous methanol at room temperature provides predominantly ortho-monoiodinated products. This acid-free method is compatible with various oxidizable functional groups.
N. C. Ganguly, S. K. Barik, S. Dutta, Synthesis, 2010, 1467-1472.
An unprecedented Rh-catalyzed direct methylation of ketones with N,N-dimethylformamide shows a broad substrate scope. Mechanistic studies suggest that DMF delivers a methylene fragment followed by a hydride during the methylation process.
Y. Li, D. Xue, W. Lu, C. Wang, Z.-T. Liu, J. Xiao, Org. Lett., 2014, 16, 66-69.
N-Acyl amino acids can be converted by oxidative decarboxylation induced by Ag+/Cu2+/S2O82- at room temperature in water into imides in good yields. Both N-benzoylvaline and N-benzoylleucine gave N-formylbenzamide, which possibly results from oxidative cleavage of an enamide intermediate.
W. Huang, M. Wang, H. Yue, Synthesis, 2008, 1342-1344.
A copper-catalyzed oxidative coupling of readily available aroylhydrazides with disulfides enables an alternative thioesterification reaction, in which oxidative expulsion of N2 overcomes the activation barrier between the carboxylic acid derivatives and the products. The reaction produces various thioesters in good to excellent yields with good functional group tolerance.
S. Xie, L. Su, M. Mo, W. Zhou, Y. Zhou, J. Dong, J. Org. Chem., 2021, 86, 739-749.
NaI-Mediated Acetamidosulphenylation of Alkenes with Nitriles as the Nucleophiles: A Direct Access to Acetamidosulfides
Y. Zheng, Y. He, G. Rong, X. Zhang, Y. Wang, K. Dong, X. Xu, J. Mao, Org. Lett., 2015, 17, 5444-5447.
(NH4)2S2O8 mediates a metal-free three-component alkene oxyalkynylation using H2O or alcohol as oxygenation agent. The reversed regioselectivity should be dictated by an alkene radical cation intermediate.
Y. Li, R. Lu, S. Sun, L. Liu, Org. Lett., 2018, 20, 6836-6839.
The use of ammonium persulfate as an oxidant and iodide as an iodine source enables stereospecific diiodination of alkynes under mild conditions in water. The highly efficient reaction provides a broad range of (E)-diiodoalkenes.
Q. Jiang, J.-Y. Wang, C.-C. Guo, Synthesis, 2015, 47, 2081-2087.
A silver-catalyzed formal [3 + 2] cycloaddition reaction, with cyclopropanols as a C3 subunit and imines as a two-atom subunit, takes place under mild conditions and produces a broad array of polysubstituted pyrroles in good yields.
Y. Zhou, M. Wu, Y. Liu, C. Cheng, G. Zhu, Org. Lett., 2020, 22, 7542-7546.
An efficient copper-catalyzed sulfenylation and selenylation of 2,3-allenoic acids with disulfides or diselenides afford various 4-sulfenylated and 4-selenylated butenolides in good yields via tandem radical addition/intramolecular cyclization processes. Moreover, 4-sulfonylated butenolides could also be obtained by sulfenylation of 2,3-allenoic acids and subsequent oxidation.
Y.-X. Xin, S. Pan, Y. Huang, X.-H. Xu, F.-L. Qing, J. Org. Chem., 2018, 83, 6101-6109.
A simple maleate-derived blocking group for pyridines enables exquisite control for Minisci-type decarboxylative alkylation at C-4 that allows for inexpensive access to a broad range of valuable building blocks. The method is operationally simple and scalable, and is applied to access known structures in a rapid and inexpensive fashion.
J. Choi, G. Laudadio, E. Godineau, P. S. Baran, J. Am. Chem. Soc., 2021, 143, 11927-11933.