Publications by authors named "Rene Hommelsheim"

Copper(I)-catalyzed domino reactions of 2-azido sulfoximines with 1-iodoalkynes yield fused triazolyl-containing benzothiadiazine-1-oxides. The protocol features the synthesis of two fused heterocyclic rings in one step with good to excellent yields and a broad functional group tolerance. Detailed mechanistic investigations indicate that a copper π-complex initiates a cycloaddition and oxidative C-N coupling reaction sequence.

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An electro-mechanochemical protocol for the synthesis of vinylic sulfoximines has been developed. Utilising mechanochemically strained BaTiO nanoparticles, the catalytic active system is generated by the reduction of copper(II) chloride. Various combinations of electron-donating and -withdrawing groups are tolerated, and the approach leads to products with difunctionalised double bonds in good to excellent yields.

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Sulfoximines are popular scaffolds in drug discovery due to their hydrogen bonding properties and chemical stability. In recent years, the role of reactive intermediates such as nitrenes has been studied in the synthesis and degradation of sulfoximines. In this work, the photochemistry of N-phenyl dibenzothiophene sulfoximine [5-(phenylimino)-5H-5λ -dibenzo[b,d]thiophene S-oxide] was analyzed.

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Upon application of a multicomponent Petasis reaction, a broad range of H-sulfoximines and boronic acids react with glyoxalic acid to afford the corresponding 2-substituted acetic acids with N-bound sulfoximidoyl groups. The protocol features excellent yields under ambient, metal-free conditions and short reaction times. Furthermore, the applicability of 2-sulfoximidoyl acetic acids as building blocks for synthesizing sulfoximine-based benzodiazepine analogues was demonstrated.

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The synthesis of trifluoromethylated cyclopropenes is often associated with important applications in drug discovery and functional materials. In this report, we describe the use of readily available chiral rhodium(II) catalysts for a highly efficient asymmetric cyclopropenation reaction of fluorinated donor-acceptor diazoalkanes with a broad variety of aliphatic and aromatic alkynes. Further studies highlight the unique reactivity of fluorinated donor-acceptor diazoalkanes in the synthesis of oligo-cyclopropenes.

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The functionalization of C-H bonds with non-precious metal catalysts is an important research area for the development of efficient and sustainable processes. Herein, we describe the development of iron porphyrin catalyzed reactions of diazoacetonitrile with N-heterocycles yielding important precursors of tryptamines, along with experimental mechanistic studies and proof-of-concept studies of an enzymatic process with YfeX enzyme. By using readily available FeTPPCl, we achieved the highly efficient C-H functionalization of indole and indazole heterocycles.

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Carbenes are very important reactive intermediates to access a variety of complex molecules and are applied widely in organic synthesis and drug discovery. Typically, their chemistry is accessed by the use of transition metal catalysts. Herein, we describe the application of low-energy blue light for the photochemical generation of carbenes from donor-acceptor diazoalkanes.

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A readily available and bench-stable cyanomethyl sulfonium salt was used in highly diastereoselective Corey-Chaykovsky cyclopropanation reactions of electron-poor olefins. This efficient method provides a rapid route to access densely functionalized cyclopropyl nitriles.

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Trifluoromethyl-substituted cyclopropanes are an attractive family of building blocks for the construction of pharmaceutical and agrochemical agents. This work demonstrated the utilization of fluorinated sulfur ylides as versatile reagents for Corey-Chaykovsky cyclopropanation reactions of nitro styrenes. This protocol favored the synthesis of cis-configured trifluoromethyl cyclopropanes for a broad range of substrates with excellent yields and good diastereoselectivities.

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Slow addition of sodium nitrite allows the in situ preparation of highly explosive diazo compounds and enables their safe and scalable application in iron catalyzed rearrangement reactions of allylic and propargylic sulfides. With catalyst loadings as low as 0.1 mol% an effective entry into α-mercapto-nitriles, α-mercapto-esters and α-trifluoromethyl-sulfides on a gram-scale is achieved.

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