Visible-light-mediated [2+2] photocycloaddition reaction can be considered an ideal solution due to its green and sustainable properties, and is one of the most efficient methods to synthesize four-membered ring motifs. Although research on the [2+2] photocycloaddition of alkynes is challenging because of the diminished reactivity of alkynes, and the more significant ring strain of the products, remarkable achievements have been made in this field. In this article, we highlight the recent advances in visible-light-mediated [2+2] photocycloaddition reactions of alkynes, with focus on the reaction mechanism and the late-stage synthetic applications. Advances in obtaining cyclobutenes, azetines, and oxetene active intermediates continue to be breakthroughs in this fascinating field of research.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1002/chem.202401501 | DOI Listing |
Angew Chem Int Ed Engl
January 2025
School of Chemistry and Chemical Engineering, Shandong University, Jinan, 250100, China.
In this contribution, we designed a new xanthate RAFT agent by introducing (5,6,7,8-tetrahydro-2-naphthalenyl)oxy (TNO) as the Z group, namely 2-[(((5,6,7,8-Tetrahydro-2-naphthalenyl)oxycarbonothioyl)thio)ethyl propanoate] (TNXEP). Due to the presence of the TNO group, TNXEP enabled highly controlled and ultrafast photoiniferter RAFT polymerization under violet (λ=405 nm) and blue (λ=450 nm) light. This approach was effectively extended to aqueous media for polymerization-induced self-assembly (PISA), facilitating the synthesis of polymeric nanoparticles.
View Article and Find Full Text PDFChem Commun (Camb)
January 2025
Key Laboratory for Advanced Materials and Institute of Fine Chemicals, School of Chemistry & Molecular Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China.
Methodological studies on the transformations of vinylidene cyclopropanes (VDCPs) have been substantially developed in the past few decades, and significant progress has been achieved in visible light-mediated, non-metal-related, and transition metal-catalyzed processes. In particular, when reactive functional groups are introduced into the backbone of VDCPs, a variety of cascade or sequential transformations can take place to produce more complex cyclic or polycyclic compounds. This review describes the recent advancements in this field.
View Article and Find Full Text PDFJ Org Chem
January 2025
Department of Chemistry, Central University of Punjab, Bathinda 151401, India.
Visible-light-driven metal- and photocatalyst-free cascade 1,4-HAT and dearomative spirocyclization of -benzylacrylamides are described for sustainable synthesis of a variety of pharmaceutically important γ-ketoamides and 2-Azaspiro[4.5]decanes in one pot in good to excellent yields. Readily accessible and nontoxic materials, expensive Ir or Ru photocatalyst-free mild conditions, excellent functional group tolerance, operational simplicity, and scalability enhance the practical value of this protocol.
View Article and Find Full Text PDFOrg Lett
January 2025
Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan.
4'-Selective alkylation of nucleosides has been recognized as one of the ideal and straightforward approaches to chemically modified nucleosides, but such a transformation has been scarce and less explored. In this Letter, we combine a visible-light-mediated photoredox catalysis and hydrogen atom transfer (HAT) auxiliary to achieve β-C(sp)-H alkylation of alcohol on tetrahydrofurfuryl alcohol scaffolds and exploit it for 4'-selective alkylation of nucleosides. The reaction involves an intramolecular 1,5-HAT process and stereocontrolled Giese addition of the resultant radicals.
View Article and Find Full Text PDFOrg Lett
January 2025
School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Thiruvananthapuram 695551, Kerala, India.
Herein, we report a formal C-C bond azidation and cyanation of unactivated aliphatic ketones using commercially available tosyl azide and cyanide, respectively. A visible-light-mediated organophotocatalyst enables radical azidation and cyanation of ketone-derived pro-aromatic dihydroquinazolinones (under mostly redox-neutral conditions) as supported by preliminary mechanistic studies. These metal-free and scalable protocols can be used to synthesize tertiary, secondary, and primary alkyl azides and nitriles with good functional group tolerance and postsynthetic diversification of the azide group, including bioconjugation.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!