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Carbon-13 NMR chemical shift substituent effects 8—3-monosubstituted 2-methylpropenes

✍ Scribed by Roberto Rittner; Mara E. F. Braibante

Publisher
John Wiley and Sons
Year
1992
Tongue
English
Weight
407 KB
Volume
30
Category
Article
ISSN
0749-1581

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✦ Synopsis

Abstract

^13^C NMR chemical shifts for some 3‐heterosubstituted 2‐methylpropenes are reported. The α‐methylene chemical shifts show excellent linear correlations with the corresponding data for some substituted carbonyl compounds (propanones, methyl acetates and N,N‐diethylacetamides). Their estimated intramolecular interaction shifts are indicative of electronic interactions between the heteroatom and the ethylenic double bond. The sp^2^ carbon shifts calculated by Dorman et al.'s method, taking a proposed set of β~σ~ and β~π~ parameters, are in close agreement with the experimental values. Neither the α‐methylene nor the olefinic carbon chemical shifts correlate well with the usual electronic and steric parameters of the substituents.

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