Intramolecular Diels-Alder Reaction of Cyclopropenyl Vinylarenes: Access to Benzonorcarane Derivatives

IntramolecularDiels-Alder vinylarene reaction (IMDAV) isa [4 + 2] cycloaddition that employs styrene derivatives as conjugateddienes, whose poor reactivity arises from the required loss of aromaticity,which is recovered by a subsequent [1,3]-H shift. Herein, we describethe use of cyclopropene as a dienophile, harnessing its strain energyto drive the IMDAV reaction. Benzonorcarane scaffolds form in goodyields, excellent stereoselectivity, and broad functional tolerance.Theoretical calculations and NMR studies have revealed significantmechanistic insights.

Automated summary

In this article, the use of cyclopropene as a dienophile for the intramolecular Diels-Alder vinylarene reaction (IMDAV) is described. The strain energy of cyclopropene is utilized to drive the reaction, resulting in good yields, excellent stereoselectivity, and broad functional tolerance. Theoretical calculations and NMR studies provide significant mechanistic insights.