Investigating the asymmetric Claisen-Cope rearrangement

The Claisen rearrangement of allylic aryl ethers typically results in the formation of ortho-allylated phenols. However, if the ortho positions are substituted, a Cope-rearrangement occurs to the para position, concluding the Claisen-Cope reaction. These [3,3]-sigmatropic rearrangements feature a transition state comprising a cyclic array of continuously bonded atoms, which enables high predictability in terms of connectivity and configuration. The aforementioned ability for stereocontrol has led to the development of a limited number of methods for the ortho Claisen rearrangement in recent years. In contrast, the asymmetric para Claisen-Cope rearrangement has been largely overlooked until now.