[反应:请参阅文本]宝石-二氟乙烯基氧杂环丁烷是合成氟化化合物的多功能构建基块。对它们与亲核试剂反应的研究导致了高度的区域选择性和立体选择性的降低。在与LiAlH4的反应中,氢化物在烯丙基环氧碳上反应,仅生成均烯丙基醇。此外,在DIBAL-H和BH3 x THF中观察到区域选择性和立体选择性S(N)2'反应。前者提供了E烯丙基醇,而后者则提供了具有出色选择性的相应Z异构体。
Synthesis of Trifluoro- or Difluoromethylated Olefins by Regio- and Stereocontrolled S<sub>N</sub>2‘ Reactions of <i>gem</i>-Difluorinated Vinyloxiranes
作者:Hisanori Ueki、Takashi Chiba、Tomoya Kitazume
DOI:10.1021/jo060089c
日期:2006.4.1
This paper presents a highly stereoselective synthesis of trifluoro- or difluoromethylated olefins via an S(N)2' type fluorination or reductions of gem-difluorinated vinyloxiranes. Their fluorination with HF-Py furnished trifluoromethylated allylic alcohols with exclusive E selectivity. On the other hand, their reduction with DIBAL-H afforded difluoromethylated E-allylic alcohols predominantly, whereas the corresponding Z isomers were formed exclusively by treatment with BH(3)center dot THF.
Regio- and Stereoselective Reductions of <i>g</i><i>em</i>-Difluorinated Vinyloxiranes
作者:Hisanori Ueki、Takashi Chiba、Tomoya Kitazume
DOI:10.1021/ol050173z
日期:2005.3.1
synthesis of fluorinated compounds. Investigations of their reactions with nucleophiles resulted in highly regio- and stereoselective reductions. In their reactions with LiAlH4, hydride reacted at the allylic epoxide carbon to produce homoallylic alcohols exclusively. Moreover, regio- and stereoselective S(N)2' reactions were observed with DIBAL-H and BH3 x THF; the former afforded E allylic alcohols
[反应:请参阅文本]宝石-二氟乙烯基氧杂环丁烷是合成氟化化合物的多功能构建基块。对它们与亲核试剂反应的研究导致了高度的区域选择性和立体选择性的降低。在与LiAlH4的反应中,氢化物在烯丙基环氧碳上反应,仅生成均烯丙基醇。此外,在DIBAL-H和BH3 x THF中观察到区域选择性和立体选择性S(N)2'反应。前者提供了E烯丙基醇,而后者则提供了具有出色选择性的相应Z异构体。