Quaternary Centers Formation via Alkene Isomerization/Claisen Rearrangement

Significance

Chiral quaternary centers can be obtained through a one-pot reaction catalyzed by a cationic iridium complex. The reaction is highly regioselective, as simple bis-allylic ethers 1 undergo isomerization only at the most accessible allylic position. A [3,3]-sigmatropic Claisen rearrangement then takes place under the reaction conditions. The reaction tolerated a wide variety of substituents on the acyclic precuror 1. The method benefits from many good methods to prepare enantiopure allylic alcohols. Importantly, it was demonstrated that chiral information can be transfered to the aldehyde 3b without erosion of ee.