Conformational dependence of isotope effects for hyperconjugating methyl groups. Nonadditivity of NMR isotope shifts in benzylic ions

DA Forsyth, P Lucas, RM Burk

文献索引：Forsyth, David A.; Lucas, Peter; Burk, Robert M. Journal of the American Chemical Society, 1982 , vol. 104, # 1 p. 240 - 245

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被引用次数: 30

摘要

Abstract: Deuterium substitution in the methyl groups induces long-range downfield shifts in" C NMR signals of the ortho and para positions of the phenyldimethylcarbenium ion. Similar downfield isotope shifts occur in I9F signals of (p-fluoropheny1) carbenium ions upon deuteration of a-methyl groups. These NMR isotope shifts are analogous to secondary@- deuterium isotope effects on rates and equilibria and arise from hyperconjugative ...