Enantioselective Rhodium-Catalyzed Dearomative Arylation or Alkenylation of Quinolinium Salts.

A highly enantioselective rhodium(I)-catalyzed dearomative arylation or alkenylation of easily available N-alkylquinolinium salts is reported, thus providing an effective and practical approach to the synthesis of dihydroquinolines in up to 99 % ee. This reaction tolerates a wide range of functional groups with respect to both the organic boronic acids and the quinoline starting materials. Moreover, the synthetic utility of this protocol is demonstrated in the formal asymmetric synthesis of bioactive tetrahydroquinoline and the total syntheses of (-)-angustureine and (+)-cuspareine.