Silylium Ion Initiated Intramolecular Friedel–Crafts-Type Cyclization of 1,1-Difluoroalkenes with Subsequent Hydrodefluorination of C(sp3)–F Bonds
作者:Avijit Roy、Haopeng Gao、Martin Oestreich、Hendrik F. T. Klare
DOI:10.1055/a-2009-8114
日期:——
reaction is presumed to be initiated by a preferential electrophilic silylation of the carbon–carbon double bond over the activation of one of the vinylic C(sp2)–F bonds. Subsequent cyclization followed by hydrodefluorination of the resulting C(sp3)–F bonds leads to the final product. The resulting tetraline derivatives were obtained in moderate to good yields. Distinct from earlier reports, the reaction
甲硅烷基离子的强亲电性已被用于探测芳基连接的 1,1-二氟烯烃的分子内 Friedel-Crafts 型环化。据推测,该反应是由碳-碳双键的优先亲电硅烷化引发的,而不是乙烯基 C(sp 2 )-F 键之一的活化。随后的环化和随后对生成的 C(sp 3 )–F 键进行加氢脱氟生成最终产物。得到的四氢化萘衍生物的收率适中。与之前的报道不同,该反应在环境条件下使用全氟化四苯基硼酸抗衡阴离子进行,而无需与硅离子中间体相关的碳酸盐抗衡阴离子作为先决条件。