Abstract
The stereoselective hydrogenation of auxiliary‐substituted quinolines was used to build up saturated and partially saturated heterocycles. In a first step, the formation and diastereoselective hydrogenation of 2‐oxazolidinone‐substituted quinolines to 5,6,7,8‐tetrahydroquinolines is reported. In this unprecedented process, stereocenters on the carbocyclic quinoline ring were formed with a dr of up to 89:11. Platinum oxide as a catalyst and trifluoroacetic acid as a solvent were found to be optimal for high levels of chemo‐ and stereoselectivity in this step. In a second hydrogenation step, the completely saturated decahydroquinolines with 4 newly formed stereocenters were obtained with enantioselectivities of up to 99%. Rhodium on carbon as a catalyst and acetic acid as a solvent gave the best results for this hydrogenation and allowed a traceless cleavage of the chiral auxiliary. Thus, this new method allows an efficient stereoselective synthesis of valuable 5,6,7,8‐tetrahydro‐ and decahydroquinoline products.