Enantioselective Olefin Cyclopropanation with G-Quadruplex DNA-Based Biocatalysts

Developing high-performance DNA-based biocatalysts for desired stereoselective syntheses remains a formidable challenge. Here, we report promising DNA-based catalysts comprised of G-quadruplex (G4) and Fe porphyrin for asymmetric olefin cyclopropanation. After the G4-based catalysts are optimized by several rounds of site mutation, their catalytic enantioselectivities achieve +81% and -86% enantiomeric excess (ee(trans)) at a turnover number (TON) as high as 500. The Fe porphyrin, binding upon the 5',3'-end G-quartet, constitutes the active center for olefin cyclopropanation via an iron porphyrin carbene intermediate. The findings provide an opportunity for generating high-value chiral cyclopropane blocks via G4 biocatalysts and shed light on the potential of DNA as protein enzymes for catalysis.