| Summary: | 碩士 === 靜宜大學 === 應用化學研究所 === 86 === Series compounds of 1-aryl-2,2,3,3-tetrafluorocyclopropanes (A) and 1-aryl-2,2-dichloro-3,3-difluorocyclopropanes (B) were prepared for studying the affects on the cyclopropane ring by the substituents on the phenyl ring via substituent chemical shifts (SCS).
During the preparation of cyclopropanes, the reactivities of dichlorocarbene and difluorocarbene toward difluorostyrene were also examined. From the rates of reactions between difluorostyrene and carbene in this series, styrenes possess the electrophile characters; the dichlorocarbene demonstrated high reactivity toward to styrenes than its difluoro counterpart.
The SCS on the C -13 NMR studies on this series of compounds showed that the substituent effect on the Cα via hyperconjugation resonance (slope = 2.459 for series A, and 2.062 for series B); while, inversed substituent effect on the Cβ, and Cγ(slope=-0.879 for Cβ, Cγ of series A; and -0.904 for Cγof series B).
The characteric fragmentation in the EI-MS of these two series were loss of a carbene fragment from the molecular ion of compounds A and elimination of a chlorine atom the molecular ion of compounds B. The later was resulted from the relative weaker bond of carbon-chlorine.
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