A series of 7-substituted allylic Grignard reagents (Me, Et, z'-Pr, Z-Bu) and a,7-dimethylallylmagnesium chloride were studied by proton nmr spectroscopy. These Grignards exist as a rapidly equilibrating mixture of Z and E primary stereoisomers (structure 1). Temperatures as low as -80°were not sufficient to stop this rapid interconversion. Protonation and coupling constant studies show that the percentage of Z isomer decreases as the size of the alkyl substituent increases: methyl, 57%; ethyl, 42%; isopropyl, 27%; tert-butyl, ~1 %. At low temperatures, the Schlenk equilibrium was detected. The stereochemical behavior of the diallyl-
7‐Methyl‐, ‐äthyl‐, ‐isopropyl‐ und ‐tert.‐butylsubstituierte Allylgrignardverbindungen und ozq‐Dimethylallylmagnesiumchlorid werden NMR‐spektroskopisch untersucht.
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