We report the application of cyclohexa-2,5-dienols in a catalytic redox isomerization: a rhodium-catalyzed desymmetrization for the synthesis of gamma,gamma-disubstituted cyclohexenones. The reaction generates products which are useful intermediates in organic synthesis, and its functional group tolerance compares favorably to that of classical redox isomerizations. Through deuteration, crossover, and competition experiments, the mechanism was found to involve an intramolecular 1,3-hydride shift. The enantioselective version of the reaction was also studied.
Divergent reactivity in tandem reduction-Michael ring closures of five- and six-membered cyclic enones
作者:Richard A. Bunce、Baskar Nammalwar、LeGrande M. Slaughter
DOI:10.1002/jhet.111
日期:2009.9
with the six-ring substrate reacting at the ester carbonyl and the five-ring substrate closing on the enone double bond. The difference in reactivity is attributed to the conformational flexibility, relative reactivity, and steric environment of C4-substituted six- and five-membered cyclicenones. J. Heterocyclic Chem., (2009).