<i>exo,exo</i>-4,8-Ethenopolyfluoro-2,6-dioxaperhydroindacenes. Unusual Alkenes Flanked with Fluorine Atoms
作者:Wojciech Dmowski、Ireneusz Nowak、Przemysław Gluziński、Andrei Kemme
DOI:10.1021/jo962023v
日期:1997.3.1
Unusual alkenes, exo,exo-4,8-etheno-1,1,3,3,5,5,7,7-octafluoro-2,6-dioxaperhydro-s-indacene (1) and exo,exo-4,8-etheno-1,1,3,3-tetrafluoro-2,6-dioxaperhydroindacene (2), as well as their nonfluorinated analogue 3 were synthesized. The structures of 1 and 3 have been determined in the solid state by X-ray crystallography and of all three compounds in solution by H-1, F-19, and C-13 NMR spectroscopy. The chemical. properties of compounds 1-3 were investigated and compared, The double bond in fluorinated polycycloalkenes 1 and 2 was found to be totally inert toward bromination, hydrogenenation, and oxidation with m-chloroperbenzoic acid and ozone. This is in contrast to nonfluorinated indacene 3, which behaves like a normal alkene, readily adds bromine and hydrogen, and reacts with oxidants. The only successful chemical transformation of I was achieved by treatment with Mn2O7, which led to oxirane 15 and rearranged pentacyclic acetal 16. An interesting skeletal rearrangement occurred in the course of bromination of 3 leading to bicyclic tetrabromo derivative 12. High chemical inertness of polyfluoroindacenes 1 and 2 has been attributed mainly to through-space electronic interactions of the double bond with proximal fluorine atoms.