A Kinetic and Structural Investigation of DNA-Based Asymmetric CatalysisUsing First-Generation Ligands

摘要

The recently developed con-cept of DNA-based asymmetric cataly-sis involves the transfer of chiralityfrom the DNA double helix in reac-tions using a noncovalently bound cata-lyst. To date, two generations of DNA-based catalysts have been reported thatdiffer in the design of the ligand forthe metal. Herein we present a studyof the first generation of DNA-basedcatalysts, which contain ligands com-prising a metal-binding domain linkedthrough a spacer to a 9-aminoacridine moiety. Particular emphasis has beenplaced on determining the effect ofDNA on the structure of the Cu~(II) com-plex and the catalyzed Diels–Alder re-action. The most important findingsare that the role of DNA is limited tobeing a chiral scaffold; no rate acceler-ation was observed in the presence of DNA. Furthermore, the optimal DNAsequence for obtaining high enantiose-lectivities proved to contain alternatingGC nucleotides. Finally, DNA has beenshown to interact with the Cu" com-plex to give a chiral structure. Compar-ison with the second generation ofDNA-based catalysts, which bear bipyr-idine-type ligands, revealed marked dif-ferences, which are believed to be re-lated to the DNA microenvironment inwhich the catalyst resides and wherethe reaction takes place.