The relevance of four-membered-ring substructures in organic
synthesis is undeniable, and well reflected by the breadth of synthetic
approaches to cyclobutanes reported in the literature. As comparatively
more versatile synthetic intermediates, cyclobutenes have been the
object of fewer studies. This account briefly reviews those prior
reports and highlights a recent breakthrough in the stereoselective,
atom-economical, and direct preparation of cyclobutenes
through an intriguing combination of photochemistry and metal catalysis.
cyclobutenes - palladium - stereoselective
synthesis - rearrangement - atom economy