Guanosine Borate Hydrogel and Self-Assembled Nanostructures Capable of Enantioselective Aldol Reaction in Water

A guanosine-based hydrogel formed by the self-assembly of guanosine and 4-((L-prolinamide)methyl)phenylboronic acid was constructed. The G quartets were selectively stabilized by K+ ions to form a self-supporting transparent hydrogel. These guanosine-derived assemblies were used to catalyze the aldol reaction in water without any additives, affording desirable conversion and enantioselectivity of the product. The controlled assays of small-molecule components indicated that the stable assemblies were the definite species that achieved high enantioselective catalysis. The current catalytic system can be readily recovered by simple extraction and still acquired good performance of the reaction after four cycles.