A stereospecific path way for the net addition of deuterium halide to a double bond was investigated using norbornene as the substrate. The polycyclic internal olefin, norbornene, has been chosen as the substrate due to its stereochemical aspects and its ability to reveal mechanistic information. The combination of hydroboration followed by halogenation in the presence of boron trihalide provides a method for the net a/trf-Markovnikov hydrohalogenation of alkenes. The Lewis acid-catalyzed halogenation of organoboranes proceeds with mostly retention of configuration at the reaction center as shown by the formation of largely exo-2- halonorboranes from fri-ejco-norbornylborane. Deuteriohalogenation of norbornene provides NMR evidence that Wagner-Meerwein rearrangement occurs: deuterium scrambling within the norbornyl halide structure shows that rearrangement occured during the halogenation reaction. This has been done for iodine and bromine as well as chlorine. Experiments have suggested that the transmercuration reaction of fr/-norbornylborane is very sensitive to steric hindrance about the boron atom. The norbornyl group, a secondary alkyl group, is not transfered readily from boron to mercury in spite of the use of Lewis acidic catalysts. This was disappointing since the resulting organomercurial could have been converted to an alkyl halide effecting the same net reaction as described above.
Library of Congress Subject Headings
Organoboron compounds; Halogenation
Department, Program, or Center
School of Chemistry and Materials Science (COS)
Han, Bo, "Deuteriohalogenation of norbornene via organoborane" (1991). Thesis. Rochester Institute of Technology. Accessed from
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