<i>S</i>-((Phenylsulfonyl)difluoromethyl)thiophenium Salts: Carbon-Selective Electrophilic Difluoromethylation of β-Ketoesters, β-Diketones, and Dicyanoalkylidenes
作者:Xin Wang、Guokai Liu、Xiu-Hua Xu、Naoyuki Shibata、Etsuko Tokunaga、Norio Shibata
DOI:10.1002/anie.201309875
日期:2014.2.10
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 CF2H group to sp3‐hybridized carbon nucleophiles such as of β‐ketoesters and dicyanoalkylidenes. The (p
S -((苯磺酰基)二氟甲基)噻吩盐是通过三氟甲磺酸催化邻乙炔基芳基二氟甲基硫烷的分子内环化反应而设计和制备的。发现噻吩盐作为将CF 2 H基团引入sp 3杂交的碳亲核试剂(如β-酮酸酯和二氰基亚烷基)的亲电子二氟甲基化试剂非常有效。的(苯磺酰基)二氟甲基可容易地转化为CF 2温和反应条件下小时。在双(金鸡纳)生物碱的存在下也实现了对映选择性亲电二氟甲基化。