Diels—Alder Reactions of Masked o‐Benzoquinones with 1‐Vinylcyclohexenes: A Short and Efficient Entry to Highly Functionalized Decahydrophenanthrene Skeleton.

Masked o-benzoquinones generated in situ from o-methoxyphenols and methanol undergo Diels—Alder reaction with 1-vinylcyclohexenes to provide decahydrophenanthrenes along with bicyclo[2.2.2]octenone derivatives.