title: S-((phenylsulfonyl)difluoromethyl)thiophenium salts: carbon-selective electrophilic difluoromethylation of β-ketoesters, β-diketones, and dicyanoalkylidenes.
abstract: S-((Phenylsulfonyl)difluoromethyl)thiophenium salts were designed and prepared by a triflic acid catalyzed intramolecular cyclization of ortho-ethynyl aryldifluoromethyl sulfanes. The thiophenium salts were found to be efficient as electrophilic difluoromehtylating reagents for introduction of a CF2 H group to sp(3) -hybridized carbon nucleophiles such as of β-ketoesters and dicyanoalkylidenes. The (phenylsulfonyl)difluoromethyl group can be readily transformed into CF2 H under mild reaction conditions. Enantioselective electrophilic difluoromethylation was also achieved in the presence of bis(cinchona) alkaloids.
authors: Department of Frontier Materials & Department of Nanopharmaceutical Science, Nagoya Institute of Technology, Gokiso, Showa-ku, Nagoya 466-8555 (Japan).
authors: Xin
authors: X
authors: Wang
authors: Guokai
authors: G
authors: Liu
authors: Xiu-Hua
authors: XH
authors: Xu
authors: Naoyuki
authors: N
authors: Shibata
authors: Etsuko
authors: E
authors: Tokunaga
authors: Norio
authors: N
authors: Shibata
mesh_terms: D003500:Cyclization; D004952:Esters / Q000737:chemistry; D006845:Hydrocarbons, Fluorinated / Q000737:chemistry; D007659:Ketones / Q000737:chemistry*; D008745:Methylation; D013237:Stereoisomerism; D013876:Thiophenes / Q000737:chemistry*
chemical_list: D004952:Esters; D006845:Hydrocarbons, Fluorinated; D007659:Ketones; D013876:Thiophenes
keywords: enantioselectivity; fluorine; regioselectivity; sulfur; synthetic methods