Diastereoselective Friedel–Crafts Alkylation of Hydronaphthalenes

An efficient and versatile synthesis of chiral tetralins
has been
developed using both inter- and intramolecular Friedel–Crafts
alkylation as a key step. The readily available hydronaphthalene substrates
were prepared via a highly enantioselective metal-catalyzed ring opening
of meso-oxabicyclic alkenes followed by hydrogenation.
A wide variety of complex tetracyclic compounds have been isolated
with high levels of regio-, diastereo-, and enantioselectivity.