New synthetic approach to α-fluoro-β-arylvinyl sulfones and their application in Diels–Alder reactions

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• 作者：Aleksey V. Shastin ; Valentine G. Nenajdenko ; Vasiliy M. Muzalevskiy ; Elizabeth S. Balenkova ; Rol ; Frö ; hlich ; Gü ; nter Haufe
• 关键词：Diels– ; Alder reaction ; Fluoroalkynes ; α ; -Fluoro-β ; -arylvinyl sulfones ; Fluoronorbornadienes ; Stereoselectivity ; Vinyl fluorides
• 刊名：Tetrahedron
• 出版年：2008
• 出版时间：6 October 2008
• 年：2008
• 卷：64
• 期：41
• 页码：9725-9732
• 全文大小：509 K

文摘

A new pathway towards α-fluoro-β-arylvinyl sulfones was elaborated. The reaction of β-bromo-β-fluorostyrenes with sodium 4-methylphenylsulfinate proceeds with maximum 94:6 stereoselectivity and 72–90 % yields. The formed α-fluoro-β-arylvinyl sulfones were found to be good dienophiles for Diels–Alder reactions with simple 1,3-dienes. From corresponding (E)-configured dienophiles and cyclopentadiene, cycloadducts bearing the fluorine substituent in exo-position were formed predominantly, while with diphenylisobenzofuran the products with endo-orientation of the fluorine were obtained as the major products. From these cycloadducts, as a proof of principle, p-toluenesulfinic acid was eliminated to give 2-fluoro-3-(4-nitrophenyl)norbornadiene, the formal [4+2]-cycloadduct of cyclopentadiene and 1-fluoro-2-(4-nitrophenyl)acetylene, or the corresponding diphenylisobenzofuran cycloadducts, respectively. This reaction was not successful when other β-hydrogen atoms are accessible for elimination.