Amino acids U 0400Highly Efficient Dynamic Kinetic Resolution of Azlactones by Urea-Based Bifunctional Organocatalysts. -The highest enantioselectivities hitherto obtained in the non-enzymatic DKR of azlactones are reported. -(BERKESSEL*, A.; CLEEMANN, F.; MUKHERJEE, S.; MUELLER, T. N.; LEX, J.; Angew. Chem., Int. Ed. 44 (2005) 5, 807-811; Inst. Org.

Aminocarboxylic acids (hydrazinocarboxylic acids) and esters P 0270Second-Generation Organocatalysts for the Highly Enantioselective Dynamic Kinetic Resolution of Azlactones. -After screening a series of bifunctional organocatalysts of the thiourea-tert.-amine-type, a system is found, which effect the alcoholytic dynamic kinetic resolution of azlactones (I) with up to 95% enantioselectivity. -(BERKESSEL*, A.; MUKHERJEE, S.; CLEEMANN, F.; MUELLER, T. N.; LEX, J.; Chem.

Aminocarboxylic acids (hydrazinocarboxylic acids) and esters Q 0440Structural Optimization of Thiourea-Based Bifunctional Organocatalysts for the Highly Enantioselective Dynamic Kinetic Resolution of Azlactones. -A number of chiral urea and thiourea derivatives such as (I)-(III) is prepared in order to test their catalytic activity in the title reaction. Among them thiourea (I) allows formation of the amino acid ester (VI) with excellent enantioselectivity. -(BERKESSEL*, A.; MUKHERJEE, S.; MUELLER, T. N.; CLEEMANN, F.; ROLAND, K.; BRANDENBURG, M.; NEUDOERFL, J.-M.; LEX, J.; Org.