Asymmetric Relay Catalysis Systems Consisting Of Gold Complex And Chiral Br(?)nsted Acid

Multi-catalysts system have emerged as a powerful tool in organic chemistry today. In these systems, the combination of multi-catalysts in one system in cooperative and relay manner may enable new transformations through the simultaneous or sequential activation and reorganization of multiple chemical bonds by the metal catalysts and organocatalysts. This concept holds great potential for application to a broad scope of organic synthetic reactions.Here we introduce an unprecedented protocol which directly transformed 2-(2-propynyl)aniline derivatives into tetrahydroquinolines in one operation with excellent enantioselectivity under the relay catalysis of an achiral Au complex and a chiral phosphoric acid. This reaction was considered a consecutive catalytic process consisting of a Au-catalyzed intramolecular hydroamination of a C-C triple bond and a Br?nsted acid catalyzed enantioselective transferhydrogenation. This work not only provides a new entry to tetrahydroquinolines complementary to the known asymmetric hydrogenation reactions of quinolines but also suggests a powerful strategy applicable to the design of transformations beyond the scope of those afforded by either Au complexes or Br?nsted acids alone.Using a similar strategy, we established an asymmetric cyclization of alkynols triggered addition of azlactones catalyzed by a combined catalyst system consisting of a chiral gold phosphate and a phosphoric acid, which results in a new strategy to convert the linear carbon-carbon triple bond functionality to a quaternary stereogenic center. This process provides a unique entry to access conformationally restricted amino acid precursors bearing vicinal quaternary stereogenic senters in high levels of stereoselectivity. In addition, this work first demonstrated that the chiral gold phosphate is able to catalyze highly enantioselective addition of azlactones to enol ethers by using chiral anion to control the stereochemistry.we have disclosed a dynamic kinetic transfer hydrogenation of 2-methyl-2,4-diaryl-2,3-dihydrobenzo[b][1,4] diazepines using phosphoric acids as catalysts. This reaction provided a synthetic approach to access 1,3-diamines in high yields with good to high ee for the major diastereomers and high to excellent ee for minor diastereomers.