Catalytic Enantioselective Nazarov Cyclization

Abstract

A detailed account of an asymmetric Nazarov cyclization that leads to α‐hydroxycyclopentenones bearing either vicinal, all‐carbon quaternary centers, or vicinal quaternary and tertiary centers is given. The all‐aliphatic examples represent the greatest challenge, as the dienone starting materials are not activated toward cyclization by an aryl group. The rational design and optimization of the substrates in parallel with optimization of the chiral Brønsted acid catalyst is also described, as well as a series of diastereoselective transformations of a fully substituted cyclopentenone product.