ABSTRACT
Artificial photoenzymes with novel catalytic modes not found in nature are in high demand; yet, they also present significant challenges in the field of biocatalysis. In this study, a chemogenetic modification strategy is developed to facilitate the rapid diversification of photoenzymes. This strategy integrates site-specific chemical conjugation of various artificial photosensitizers into natural protein cavities and the iterative mutagenesis in cell lysates. Through rounds of directed evolution, prominent visible-light-activatable photoenzyme variants were developed, featuring a thioxanthone chromophore. They successfully enabled the enantioselective [2 + 2] photocycloaddition of 2-carboxamide indoles, a class of UV-sensitive substrates that are traditionally challenging for known photoenzymes. Furthermore, the versatility of this photoenzyme is demonstrated in enantioselective whole-cell photobiocatalysis, enabling the efficient synthesis of enantioenriched cyclobutane-fused indoline tetracycles. These findings significantly expand the photophysical properties of artificial photoenzymes, a critical factor in enhancing their potential for harnessing excited-state reactivity in stereoselective transformations.
Subject(s)
Cycloaddition Reaction , Stereoisomerism , Indoles/chemistry , Indoles/chemical synthesis , Indoles/metabolism , Photochemical Processes , Biocatalysis , Directed Molecular Evolution , Photosensitizing Agents/chemistry , Photosensitizing Agents/chemical synthesis , Light , Escherichia coli/enzymology , Molecular StructureABSTRACT
An efficient and CO2-promoted dehydroxylative coupling of benzylic alcohols catalyzed by ligand-free cuprous chloride has been achieved. The discovered catalytic reductive coupling reaction is a newly C-C bond-forming transformation of alcohols. Mechanistic insight is gained through control reactions.
ABSTRACT
A visible-light-induced radical gem-iodoallylation of CF3CHN2 was developed under mild conditions, delivering a variety of α-CF3-substituted homoallylic iodide compounds in moderate to excellent yields. The transformation features broad substrate scope, good functional group compatibility, and operational simplicity. The described protocol provides a convenient and attractive tool to apply CF3CHN2 as CF3-introduction reagent in radical synthetic chemistry.
ABSTRACT
Multi-component reaction of higher degree ultilization of diazo molecules for polyene formation is highly intriuging but still underexplored. We present herein an unprecedented coupling of 2,2,2-trifluorodiazoethane and aryl alkynes mediated by iodine under visible light. The multi-component reaction involving two diazo units and two alkyne units provides a straightforward and step-economic access to bistrifluoromethylated 1,3,5-trienes in high stereoselectivity by creation of three CâC bonds in a single step under mild conditions.
ABSTRACT
Five new heterobimetallic magnesiates bearing bidentate dianionic pyrrolyl ligands have been synthesized through co-complexation with alkali-metal reagents and di-n-butylmagnesium. Single-crystal X-ray structural analysis of these complexes revealed a variety of intriguing bonding modes. These alkali-metal (Li, Na, and K) organomagnesiates were utilized as catalysts for cross-coupling Tishchenko reactions with two different aldehydes. The sodium alkyl magnesiate complex {nBuMg[2-(Me3CNCH2)C4H3N]Na(Et2O)}∞ (3) was identified as a competent catalyst, as it exhibited higher catalytic activities and chemoselectivity under mild conditions.
