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Stereochemistry of the Elimination of Norcamphor‐ and Apocamphor Tosylhydrazone with Methyllithium
Author(s) -
Liu KwangTing,
Shapiro Robert H.
Publication year - 1969
Publication title -
journal of the chinese chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.329
H-Index - 45
eISSN - 2192-6549
pISSN - 0009-4536
DOI - 10.1002/jccs.196900007
Subject(s) - chemistry , methyllithium , norbornene , deuterium , ether , selectivity , stereochemistry , kinetic isotope effect , medicinal chemistry , organic chemistry , physics , monomer , quantum mechanics , catalysis , polymer
Upon treatment with three equivalents of methyllithium in ether at room temperature exo ‐3‐ d ‐norcamphor tosylhydrazone gave norbornene which retained 21% of the deuterium and exo ‐3‐ d ‐apocamphor tosylhydrazone gave apobornylene which retained 50% of the deuterium based on nmr and mass spectral analysis. In both cases exo ‐elimination is favored when the primary isotope effect is considered. The relatively low selectivity between exo ‐and endo ‐elimination as compared with that observed in solvolytic studies was tentatively rationalized by the carbarion character of the transition state leading to proton abstraction by the base.