No abstract

A new type of DNA metal complex hybrid catalyst, which is based on single-stranded DNA oligonucleotides, is described. It was shown that oligonucleotides as short as 14 nucleotides that fold into hairpin structures are suitable as nucleic acid components for DNA hybrid catalysts. With these catalysts, excellent enantioinduction in asymmetric Diels-Alder reactions with selectivity values as high as 96 % enantiomeric excess (ee) can be achieved. Molecular dynamics simulations indicate that a rather flexible loop combined with a rigid stem region provides DNA scaffolds with these high selectivity values.

Nucleic acids can form efficient hybrid catalysts for asymmetric catalysis upon binding of low-molecular-weight metal complexes. Up to now DNA has been the preferred nucleic acid component, while RNA was largely ignored. It is shown that despite RNA's successful use in ribozymes, RNA is less suited for use in hybrid catalysts for asymmetric catalysis. A common dimethyl bipyridine copper complex does not form highly active and enantioselective hybrid catalysts with RNA due to the absence of synergistic effects between the copper complex and dsRNA.

DNA oligonucleotides that fold into hairpin structures are suitable nucleic acid components for the formation of DNA hybrid catalysts. In combination with a low‐molecular‐weight copper complex, these catalysts induce excellent enantioselectivity in asymmetric Diels–Alder reactions with selectivity values as high as 96% enantiomeric excess (ee). Molecular dynamics simulations revealed that the nucleic acid components adopt a conformation with flexible loops, but a rigid, B‐DNA‐like stem region. More information can be found in the Communication by A. Heuer and U. Hennecke et al. on page 6004 ff.