Comparative study of the ring opening of 1-CF₃-epoxy ethers mediated by Brönsted acids and hexafluoro-2-propanol

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• 作者：Jernej Iskra ; Daniè ; leBonnet-Delpon ; Jean-Pierre Bé ; gué
• 关键词：Fluorinated alcohols ; Hexafluoro-2-propanol ; Trifluoromethyl-epoxy ethers ; Trifluoromethyl ketones ; Oxirane ring-opening ; Hydrogen bonds ; Brö ; nsted acid
• 刊名：Journal of Fluorine Chemistry
• 出版年：2005
• 出版时间：April 2005
• 年：2005
• 卷：126
• 期：4
• 页码：549-554
• 全文大小：218 K

文摘

In order to evaluate more deeply the nature of the activation of oxirane ring opening reactions by HFIP, ring opening of both CF₃-epoxy ethers 1a (R = Ph) and 1b (R = CH₂CH₂Ph) with HFIP alone, and with hard (MeOH) or soft (PhSH) nucleophiles in HFIP, were investigated and compared to reactions performed with Brönsted acids. Nucleophilic ring opening reactions in HFIP were facilitated with PhSH and only α-substituted trifluoromethyl ketone 5 was isolated (nucleophilic ring opening), while with MeOH, both processes, nucleophile and electrophile-assisted ring opening were in competition. In the Brönsted acid-catalysed ring opening of 1-CF₃-epoxy ethers 1 in HFIP, only the acid-catalysed ring opening process occurred with an inversed regioselectivity.