Visible-Light-Driven Deoxygenative Heteroarylation of Alcohols with Heteroaryl Sulfones.

The visible-light-promoted deoxygenative radical heteroarylation of alcohols was achieved in the absence of any external photosensitizers. The processes occur through the generation of xanthate salts from alcohols, followed by SET and fragmentation, delivering alkyl radicals to react with heteroaryl sulfones. This method is amenable for a wide range of alcohols with good functional group tolerance, providing a practical strategy for the alkylation of benzo-heteroaromatics. Mechanism studies indicate that direct visible-light excitation of xanthate anions and subsequent SET initiate the reactions.

Visible-Light-Driven Multicomponent Reactions for the Versatile Synthesis of Thioamides by Radical Thiocarbamoylation.

Thioamides are widely used structures in pharmaceuticals and agrochemicals, as well as important synthons for the construction of sulfur-containing heterocycles. This report presents a series of visible-light-driven multicomponent reactions of amines, carbon disulfide, and olefins for the mild and versatile synthesis of linear thioamides and cyclic thiolactams. The use of inexpensive and readily available carbon disulfide as the thiocarbonyl source in a radical pathway enables the facile assembly of structurally diverse amine moieties with non-nucleophilic carbon-based reaction partners. Radical thiocarbamoylative cyclization provides a practical protocol that complements traditional approaches to thiolactams relying on deoxythionation. Mechanistic studies reveal that direct photoexcitation of in situ formed dithiocarbamate anions as well as versatile photoinduced electron transfer with diverse electron acceptors are key to the reactions.

Deoxygenative coupling of alcohols with aromatic nitriles enabled by direct visible light excitation.

A general and practical protocol is presented for visible-light-driven deoxygenative coupling of alcohols with aromatic nitriles in the absence of external photocatalysts. Utilizing a hydroxyl activation strategy with carbon disulfide, this C(sp3)-C(sp2) constructing platform accommodates a broad scope of alcohols and aryl nitriles to deliver various alkyl-substituted arenes. Mechanism studies show that a single electron transfer event between a photoexcited aryl nitrile and a xanthate anion is key to the transformation.

Separation of the Sound Power Spectrum of Multiple Sources by Three-Dimensional Sound Intensity Decomposition.

The identification and separation of sources are the prerequisite of industrial noise control. Industrial machinery usually contains multiple noise sources sharing same-frequency components. There are usually multiple noise sources in mechanical equipment, and there are few effective methods available to separate the spectrum intensity of each sound source. This study tries to solve the problem by the radiation relationship between three-dimensional sound intensity vectors and the power of the sources. When the positions of the probe and the sound source are determined, the sound power of the sound source at each frequency can be solved by the particle swarm optimization algorithm. The solution results at each frequency are combined to obtain the sound power spectrum of each sound source. The proposed method is first verified by a simulation on two point sources. The experiment is carried out on a fault simulation test bed in an ordinary laboratory; we used three three-dimensional sound intensity probes to form a line array and conducted spectrum separation of the nine main noise sources. The sound intensity on the main frequency band of each sound source was close to the result of the near-field measurement of the one-dimensional sound intensity probe. The proposed spectral separation method of the sound power of multiple sound sources provides a new method for accurate noise identification in industrial environments.