N‑Heterocyclic Carbene-Catalyzed Enantioselective Intramolecular N‑Tethered Aldehyde–Ketone Benzoin Reactions

The N-heterocyclic carbene-catalyzed enantioselective intramolecular benzoin reaction of N-tethered substrates was realized. With 15 mol % of d-camphor-derived triazolium salt E and 10 mol % of NaOAc, the aldehyde–ketone cross benzoin reactions of various substituted N-tethered substrates proceeded smoothly to afford dihydroquinolinone derivatives with a quaternary carbon stereocenter in moderate to good yields and excellent ee.