cis-trans Isomeric and Substituent Effects on the Lanthanide Induced Shifts in 2-Phenylcyclopropanic System

摘要

LIS`s of cis and trans-methyl-2-phenylcyclopropanecarboxylate, cis and trans-t-butyl-2-phenylcyclopropanecarboxylate, cis and trans-N,N-dimethylcyclopropanecarboxamide, trans-2-phenylcyclopropyl methyl ketone and trans-2-phenylcyclopropyl t-butyl ketone have been studied. The LIS`s hold the McConnell-Robertson relation and are mainly influenced by the steric effect. LIS`s of trans isomers are larger than those of cis isomers. In trans isomers, the LIS`s decrease in the following order: methyl ketone > methyl ester > N,N-dimethyl amide > t-butyl ketone…t-butyl ester.