Redox-Divergent Chiral Phosphoric Acid-Catalyzed Enantioselective Formal Quinone Diels-Alder Reactions.

An efficient enantioselective construction of tetrahydronaphthalene-1,4-diones as well as dihydronaphthalene-1,4-diols via a chiral phosphoric acid catalyzed quinone Diels-Alder reaction with dienecarbamate was reported. The nature of the protected group on diene was key to the success showing a remarkable influence for achieving high enantioselectivity. The divergent "redox" selectivity is controlled by adequate amount of quinones used. Reversible redox switching without erosion of enantioselectivity was possible from individual redox isomers.