Methods to assemble alkynes are essential for synthesizing fine chemicals, pharmaceuticals and polymeric photo-/electronic materials. Using light as a clean energy form and water as a green solvent has the potential to make synthetic chemistry more environmentally friendly. Here we present a transition-metal-free coupling protocol between aryl alkyne and alkyl iodide enabled by photoenergy in water. Under ultraviolet irradiation and in basic aqueous media, aryl alkynes efficiently couple with a wide range of alkyl iodides including primary, secondary and tertiary ones under mild conditions. A tentative mechanism for the coupling is also proposed.
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http://dx.doi.org/10.1038/ncomms7526 | DOI Listing |
Org Lett
January 2025
Key Laboratory of Precision and Intelligent Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, China.
A 1,1-hydroboration of alkynylgermanes with unique -Ge/B stereochemistry under transition-metal-free conditions is reported. Mechanistic studies suggest that a pathway involving α-boration followed by a stepwise 1,2-Ge/H shift on the intermediate structurally lies between an alkyne-Ge π complex and a typical vinyl cation. The resulting Ge/B bimetallic modules, along with a /Ge/B trimetallic variant, can be conveniently transformed into trisubstituted olefins through iterative divergent cross-coupling.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224, Warsaw, Poland.
The development of straightforward synthetic methods for photoactive polycyclic aromatic hydrocarbons (PAHs) that avoid Pd-catalyzed or radical-based processes remains a challenge. Such methods are essential to reducing the cost and environmental impact of organic photodevices. In this work, we present a one-pot synthetic approach for creating novel bipolar PAHs with extended π-conjugation, which are not accessible via conventional Pd-catalyzed routes.
View Article and Find Full Text PDFJ Org Chem
January 2025
Department of Chemistry, Birla Institute of Technology and Science Pilani, Pilani Campus, Rajasthan 333031, India.
A convenient and efficient transition-metal-free method has been developed for the C(sp)-H alkoxylation/aryloxylation of 1,4-quinones by direct cross-dehydrogenative coupling with readily available alcohols and phenols in the presence of TEMPO under simple and mild conditions. The method allowed the installation of a wide range of alkoxy/aryloxy groups, exhibited high functional group tolerance, showed a broad substrate scope, afforded good to excellent yields of products in a simple one-pot operation, and could be performed on a gram scale. Mechanistic investigation indicated the involvement of the radical pathway.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Department of Chemistry, Texas A&M University, PO Box 30012, College Station, TX 77842-30012.
The functionalization of pyridines at positions remote to the N-atom remains an outstanding problem in organic synthesis. The inherent challenges associated with overriding the influence of the embedded N-atom within pyridines was overcome using n-butylsodium, which provided an avenue to deprotonate and functionalize the C4-position over traditionally observed addition products that are formed with organolithium bases. In this work, we show that freshly generated 4-sodiopyrdines could undergo transition metal free alkylation reactions directly with a variety of primary alkyl halides bearing diverse functional groups.
View Article and Find Full Text PDFOrg Biomol Chem
December 2024
College of New Energy, State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China) 266580, Qingdao, P. R. China.
A photocatalytic dearomative hydrosilylation reaction of indole derivatives with silanes has been accomplished for the synthesis of valuable indolinyl silanes through a carbon-silyl radical coupling process with the cooperation of photoredox and hydrogen atom transfer catalytic systems composed of 3DPA2FBN (2,4,6-tris(diphenylamino)-3,5-difluorobenzonitrile), (i-Pr)SiSH, and base additives. This protocol is featured by a broad substrate scope, transition metal-free conditions, high diastereoselectivities and applications in natural product derivatives.
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