Diene-Transmissive Enantioselective Diels–Alder Reactions and Sequences Involving Substituted Dendralenes

Readily available and stable substituted [3]­dendralenes undergo highly chemo-, regio-, diastereo-, and enantioselective organocatalyzed Diels–Alder reactions with acrolein to form enantiomerically enriched cycloadducts. These monocycloadducts carry semicyclic dienes that undergo a second, substrate-controlled diastereoselective Diels–Alder reaction with a different dienophile to form 2-fold cycloadducts. Overall, annulated, functional group rich, chiral Δ1(9)-octalin building blocks are accessed in one-pot operations that significantly extend the preparative value of diene-transmissive Diels–Alder sequences since they offer products of regio- and stereochemistry complementary to those generated from the parent, unsubstituted [3]­dendralene.