Bloch, J. M.; Savelson, E.; Meng, A. Q.; Ericson, M. N.; Patel, I. U.; Dickie, D. A.; Tepe, J. J.; Harman, D. Tungsten-Enabled Diels—Alder Cycloaddition and Cycloreversion of Arenes and Alkynes: Divergent Synthesis of Highly Functionalized Barrelenes and Arenes. J. Am. Chem. Soc. 2025.
Abstract
The Diels—Alder reaction of benzenes remains a significant synthetic challenge, owing to their highly stabilized aromatic cores. In this work, the dearomatization agent \WTp(NO)(PMe3)\ is used to promote Diels—Alder reactions of dihapto-coordinated ($η$2) benzenes with alkynes. The resulting $η$2-barrelene complexes can be oxidized to liberate intact barrelenes. Alternatively, mild pyrolysis leads to the extraction of the corresponding tungsten-acetylene complex and concomitant formation of new arenes possessing substituents originating from the acetylene dienophiles.