Studies on the effects of substituents on rate enhancements in intramolecular diels-alder reactions: Reasons for the gem-dimethyl effect
作者:Michael E. Jung、Jacquelyn Gervay
DOI:10.1016/s0040-4039(00)87899-5
日期:1988.1
Comparison of the rates of cyclization of a series of 2-furfuryl methyl fumarates leads to the conclusion that the gem-dimethyl effect is due primarily to higher population of reactive rotamers.
gem-Dialkyl effect in the intramolecular Diels-Alder reaction of 2-furfuryl methyl fumarates: the reactive rotamer effect, the enthalpic basis for acceleration, and evidence for a polar transition state
作者:Michael E. Jung、Jacquelyn Gervay
DOI:10.1021/ja00001a032
日期:1991.1
Investigation of the rates of cyclization of a series of substituted 2-furfurylmethylfumarates has allowed us to determine which of the two explanations for the gem-dialkyl effect is more important. Studies with compounds substituted with small-membered rings showed that the rate acceleration is due primarily to the reactive rotamer effect and not to angle compresion («Thorpe-Ingold effect»)