Lightening Diazo Compounds

Herein, we report visible light and N-heterocyclic carbene (NHC) jointly promoted multicomponent carbene transfer reactions. Under the optimized reaction conditions, two kinds of important hydroxamic acid esters were obtained in good yields depending on the reaction media used. The key to this success was driven by the blue light-promoted generation of free carbene species and the fast in situ formation of hydroxamic acid under NHC-catalyzed conditions. The mild reaction conditions, excellent functional group tolerance, useful synthetic transformations, and successful modification of natural products and drug molecules proved the utility and practicality of this method. 

Dark and Light Reactions of Carbenes─Merging Carbene Transfer Reactions with N-Heterocyclic Carbene Catalysis for the Synthesis of Hydroxamic Acid Esters

A blue light-promoted reaction between aryldiazoacetates and different nucleophiles has been developed in the presence of THF (and other cyclic ethers) as solvent, allowing the incorporation of these three elements...

A Visible Light-Mediated Three-Component Strategy Based on the Ring-Opening of Cyclic Ethers with Aryldiazoacetates and Nucleophiles

Solar-driven straightforward one-step synthesis of pyridine derivatives in the absence of photosensitizer is of considerable interest but greatly challenging in synthetic and medicinal chemistry. Herein, an unprecedented 2-fold interpenetrated lvt polyoxometalate-based open framework (POM-OF), LCU-22 ([Zn(1-ipIM) 3 ] 2 [Zn 6 (AsW 9 O 33 ) 2 (1-ipIM) 6 ]·2(1-HipIM), 1-ipIM = 1-isopropyl imidazole) has been synthesized in gram-scale quantities using a one-pot reaction and structurally characterized by X-ray crystallography. The cluster node in LCU-22 is a Zn 6 ring seamed trivacant polyoxotungstate cluster ([Zn 6 (AsW 9 O 33 ) 2 ]), which is quadruply extended by [Zn(1-ipIM) 3 ] 2+ units to form the final 3D open framework. Remarkably, LCU-22 is highly stable over wide pH range and in various solvents, and dramatically boosted the white light-powered heterogeneous photocatalysis for synthesis of pyridine derivatives in good yields after three times recycles utilization. This work not only build a novel POM-OF but also underscores the unique advantages of transition metal cluster substituted polyoxotungstates frameworks used for selective photocatalytic formation of value-added organic molecules. • The one-pot gram-scale synthetic strategy has been reported for 2-fold interpenetrated lvt LCU-22 . • LCU-22 is highly stable over wide pH range and in various solvents • LCU-22 boosted the visible-light-driven heterogeneous photocatalysis for one-step synthesis of pyridine derivatives. • The catalysis mechanism of the photocatalyst has been intensively discussed and revealed. 

An Unprecedented 2-fold Interpenetrated lvt Open Framework Built from Zn6 Ring Seamed Trivacant Polyoxotungstates Used for Photocatalytic Synthesis of Pyridine Derivatives

Herein we report a series of telescoping methodologies for one pot synthesis of biologically relevant γ-carboline derivatives 6 and spiro[pyrrolidinone-3,3']indole 7. Initially the three consecutive steps of cyclopropanation, phthalimide deprotection, and Boc-deprotection have been congregated in a single reaction vessel to afford a ∼1:1 mixture of 6 and 7. Next, careful optimization of the reaction sequence and the conditions generated an orthogonal approach to access compounds 6 and 7 exclusively. Air oxidation of the γ-carbolinones 6 afforded aromatic γ-carbolines 8.

Orthogonal Syntheses of γ-Carbolinone and Spiro[pyrrolidinone-3,3']indole Derivatives in One Pot through Reaction Telescoping.

Mild blue light-mediated N-H insertion of indole and its derivatives into aryldiazoesters has been reported in a batch and flow strategy to afford the corresponding N-alkylated product in moderate-to-excellent yield. Detailed high-performance liquid chromatography-based reaction kinetics measurements, control experiments, and kinetic isotope effect reveal that 3-substituted indoles with electron-withdrawing groups such as -CN and -CHO facilitated the product formation, whereas the electron-donating group retarded the process. The neutral indole performed in between them. Furthermore, Hammett plot and density functional theory-based transition-state optimization studies showed substantial correlation of the electronic nature of the substituents at the C3 position of indoles with the rate of the N-H insertion reaction. The strategy was utilized to synthesize a key intermediate for the natural product (-)-psychotrimine.

Blue LED-Mediated N-H Insertion of Indoles into Aryldiazoesters at Room Temperature in Batch and Flow: Reaction Kinetics, Density Functional Theory, and Mechanistic Study.

Photolytic amino etherification reactions of aryl diazoacetates with N-heterocycles and a stoichiometric amount of dioxane/tetrahydropyran in aqueous medium: synthesis of 1,4-dioxepane/1,4,7-dioxazonan-6-one systems

Blue LED induced solvent-free multicomponent reaction among aryl diazoacetates, pyridine derivatives and maleimides: Direct eco-friendly synthesis of densely functionalized Itaconimides

Blue light-emitting diode-mediated environmentally sustainable three component reactions among pyridine/isoquinoline 1/2, aryl diazoesters 3, and acrylic ester/3-alkenyl oxindoles 5/6 provide various dihydroindolizines 7 to 9 in excellent yield. The principle of the strategy is photolytic generation of nitrogen ylides from N-heteroarenes and aryl diazoesters and their subsequent [3 + 2] cycloaddition reaction with dipolarophiles. Detailed mechanistic analysis of the transformation through control experiments establishes this strategy as the foundation for the photolytic multicomponent reaction.

Blue Light-Emitting Diode-Mediated In Situ Generation of Pyridinium and Isoquinolinium Ylides from Aryl Diazoesters: Their Application in the Synthesis of Diverse Dihydroindolizine.

A One Pot Diazo Installation-Photochemical Oxidation (Blue Led-O2)/ Amidation of Aryl/Heteroaryl Acetates with Cyclic 2°-Amines: An Eco-Friendly Synthesis of Aromatic Α-Ketoamides

Debajit Maiti

Papers

Blue LED-Mediated N-H Insertion of Indoles into Aryldiazoesters at Room Temperature in Batch and Flow: Reaction Kinetics, Density Functional Theory, and Mechanistic Study.

Photolytic amino etherification reactions of aryl diazoacetates with N-heterocycles and a stoichiometric amount of dioxane/tetrahydropyran in aqueous medium: synthesis of 1,4-dioxepane/1,4,7-dioxazonan-6-one systems

Blue LED induced solvent-free multicomponent reaction among aryl diazoacetates, pyridine derivatives and maleimides: Direct eco-friendly synthesis of densely functionalized Itaconimides

Blue Light-Emitting Diode-Mediated In Situ Generation of Pyridinium and Isoquinolinium Ylides from Aryl Diazoesters: Their Application in the Synthesis of Diverse Dihydroindolizine.

A One Pot Diazo Installation-Photochemical Oxidation (Blue Led-O2)/ Amidation of Aryl/Heteroaryl Acetates with Cyclic 2°-Amines: An Eco-Friendly Synthesis of Aromatic Α-Ketoamides