Water undoubtedly is an ideal solvent for the asymmetric catalysis from economical and environmental points of view.Yet,successful performing asymmetric reaction in water was restricted by the poor water-solubility of substrates and/or catalysts.In nature,enzymes are efficient biocatalysts that regulate a broad variety of biochemical reactions in aqueous environments in nature.The catalytic properties result from guided three-dimensional folding of a single protein chain,which gives a compartmentalized structure with hydrophobic cores surrounded by hydrophilic shells.Inspired by nature,we have designed a series of light/thermo-responsive random copolymers.The copolymers self-folded in reaction systems through intrachain metal complexation and/orintramolecularhydrophobicinteraction,forming compartmentalized single-chain polymeric nanoparticles?SCPNs?with a hydrophobic,catalytically active interior.The compartmentalized SCPNs acted as catalytic nanoreactors,enriching catalytic motifs and substrates in a confined hydrophobic interior,which thus accelerated the asymmetric catalysis in water.After reaction,they could be facilely recovered for reuse by simple light-or thermo-stimuli.?1?Chiral salen Cr?III?complexes?Cr?salen??were encapsulated in thermo-responsive polymer nanoreactors through folding an amphiphilic random copolymer of poly?N-isopropylacrylamide-co-IL/Cr?salen??(poly?NIPAAM-co-IL/Cr?salen??around Cr?salen?in water.The resulted catalytic nanoreactors exhibited several advantages over the traditional Cr?salen?system for asymmetric epoxidation of alkenes in water.First,they were dispersed in water,behaving as a quasi-homogeneous catalyst for the aqueous asymmetric epoxidation.Second,they effectively sequestered substrates from the surrounding environment,creating a highly concentrated environment for efficient catalysis.Third,water was excluded from the nanoreactor,minimizing the undesired hydrolysis of epoxides.As a result,the compartmentalized catalysts mediated aqueous asymmetric epoxidation with unprecedented yields?92–95%?and enantioselectivities?ee,92–99%?,whereas traditional Cr?salen?catalyst was far less efficient?4-12%of yields and 29-44%of ee?.Thanks to the themo-sensitive of NIPAAm shell,the catalytic nanoreactor could be facilely recovered for reuse by thermo-controlled separation.?2?Metalloenzyme is a source of inspiration for chemists who attempt to create versatile synthetic catalysts for aqueous catalysis.Herein,we imparted metalloenzyme-like characteristics to chiral FeII-oxazoline complex by incorporating Fe?II?ion into chiral oxazoline-containing discrete self-folded polymer,to realize the highly enantioselective sulfa-Michael addition?SMA?in water.Intrachain FeII-oxazoline complexation together with hydrophobic interaction triggered the self-folding of oxazoline-containing single polymeric chain in water.The formed FeII-folded SCPNs significantly accelerated the aqueous asymmetric SMA reaction via self-folded hydrophobic compartment around the catalytic sites,reminiscent of metalloenzymatic catalysis.Only 3.0 mol%of the FeII-folded SCPNs was sufficient to give almost quantitative yield?90-96%?of a wide range of chiral?-thioketones with high enantioselectivity?90–99%?in water without the use of any additives.In addition,they could be facilely recovered for reuse by simple thermo-controlled separation due to thermo-responsive properties.?3?Thermocontrolled catalysis often acquires high costs in energy consumption,if operated in a large volume.Herein,we have developed a series of photoresponsive,amphiphilic diblock copolymers of PSxOy which composed of a photoresponsive nitrospiropyran block and hydrophobic chiral oxazoline ligand block via RAFT technology.Intrachain TiIV-oxazoline complexation together with hydrophobic interaction triggered the self-folding of the PSxOy in water.The formed TiIV-folded SCPNs exhibited visible-light-controlled water-solubility behavior due to the negative photochromism of nitrospiropyran shell.In the dark,the nitrospiropyran block was in MC?hydrophilic?form.The SCPNs,which composed of hydrophilic MC surfaces and hydrophobic TiIV-oxazoline cores,acted as water-soluble catalytic nanoreactor to accelerate the asymmetric sulfoxidation in water.Under visible-light irradiation,the catalytic nanoreactor became hydrophobic due to the re-formation of nitrospiropyran?hydrophobic?.They were thus collapsed and spontaneously precipitated from the aqueous system for recovery.The photo-responsive TiIV-folded SCPNs thus typically realized the visible-light-controlled reaction-separation for asymmetric sulfoxidation in water. |