New elements in the gold(I)-catalyzed cycloisomerization of enynyl ester derivatives embedding a cyclohexane template

The gold-catalyzed cycloisomerization of enynyl esters bearing a cyclohexyl template has been studied and has been shown to lead to two types of products arising from 1,2- vs. 1,3-O-acyl-migration. Results have shown to be dependent on the nature of the solvent, the catalysts, the migrating group, the stereochemistry of the starting diastereomer as well as the alkene partner. This set of findings confirms the intricate nature of the “golden carousel” of propargylic acetates.

When the following prenyl enyne precursor is treated with Echavarren’s gold catalyst, a cycloisomerization featuring a 1,2-O-acyl migration takes place, delivering a tricyclic derivative in good yield and as a single diastereomer. Variations around the catalyst, the structure of the precursors and reaction conditions have been studied.Figure optionsDownload as PowerPoint slideResearch highlights
► New elements in the reactivity of enynyl ester bearing a cyclohexyl template in the presence of electrophilic gold complexes.
► New applications of the Rautenstrauch rearrangement for the diastereoselective formation of functionalized carbocyclic platforms.
► Golden carousel (1,2- vs. 1,3-O-acyl-migration) in a cyclic system.