Ene Reactions of Conjugated Dienes. 2. Dependence of Rate on Degree of Hydrogen Removed and s-Cis or s-Trans Diene Character

Article abstract of DOI:10.1021/jo00202a011

The rates of the ene reactions between diethyl diazenedicarboxylate and a number of dienes have been measured and product structures determined.Accelerated reactions are observed with 1,3-cyclohexadienes but not with dienes held fixed in the s-trans form.Within the first set of systems tertiary hydrogens are much more reactive than secondary.Within the second set secondary are (in turn) more reactive than primary.There is no apparent correlation between the rate of the Diels-Alder reaction of the 1,3-cyclohexadienes with maleic anhydride and the rate of ene reaction with the diazenedicarboxylate.