Cyclic Dinucleotide-Based Enantioselective Fluorination in Water.

The diverse structures of DNA serve as potent chiral scaffolds for DNA-based asymmetric catalysis, yet in most cases tens to hundreds of nucleotides in DNA hybrid catalysts hinder the deep insight into their structure-activity relationship. Owing to the structural simplicity and design flexibility of nucleotides, nucleotide-based catalysts have been emerging as a promising way to obtain fine structural information and understand the catalytic mechanisms. Herein, we found that a cyclic dinucleotide of cyclic di-AMP (c-di-AMP) and 1,10-phenanthroline copper(II) nitrate (Cu(phen)(NO 3 ) 2 ) are assembled to a c-di-AMP-based catalyst (c-di-AMP/Cu(phen)(NO 3 ) 2 ), which could fast achieve enantioselective fluorination in water with 90-99% yields and up to 90% enantiomeric excess (ee). The host-guest interaction between c-di-AMP and Cu(phen)(NO 3 ) 2 has been proposed mainly in a supramolecular interaction mode as evidenced by spectroscopic techniques of ultraviolet-visible, fluorescence, circular dichroism, and nuclear magnetic resonance. Cu(phen)(NO 3 ) 2 tightly binds to c-di-AMP with a binding constant of 1.7 ± 0.3 × 10 5 M -1 , and the assembly of c-di-AMP/Cu(phen)(NO 3 ) 2 shows a modest rate enhancement to carbon-fluorine bond formations as supported by kinetic studies.