esters providing α-trifluoromethylthio-β-keto esters in good to high yields. α-Methylene-β-keto sulfones were also accepted as substrates by CF3-DAST to furnish the corresponding α-trifluoromethylthio compounds. This strategy can be extended to perfluoroalkylthiolation reactions using perfluoroethyl-DAST (C2F5-DAST) and perfluoropropyl-DAST (C3F7-DAST).
Construction of Fluorinated Benzoxathiin Skeleton by Successive Perfluorophenylthiolation/Cyclization of Activated α-Methylene Ketones by Perfluorophenyl Diethylaminosulfur Difluoride
fluorinated benzoxathiin (thiaflavan) skeleton 4 was directly constructed by the reaction of activated α-methylene ketones 1 such as β-keto esters, 1,3-diketone, and β-ketosulfones with a perfluorophenyl analogue of diethylaminosulfur trifluoride, C6F5-DAST, in high yields via successive perfluorophenylthiolation/cyclization reaction.
Enantioselective Copper-Catalyzed Decarboxylative Propargylic Alkylation of Propargyl β-Ketoesters with a Chiral Ketimine P,N,N-Ligand
作者:Fu-Lin Zhu、Yuan Zou、De-Yang Zhang、Ya-Hui Wang、Xin-Hu Hu、Song Chen、Jie Xu、Xiang-Ping Hu
DOI:10.1002/anie.201309182
日期:2014.1.27
The first enantioselective copper‐catalyzed decarboxylative propargylic alkylation has been developed. Treatment of propargyl β‐ketoesters with a catalyst, prepared in situ from [Cu(CH3CN)4BF4] and a newly developed chiral tridentate ketimine P,N,N‐ligand under mild reaction conditions, generates β‐ethynyl ketones in good yields and with high enantioselectivities without requiring the pregeneration