We report a radical-stabilization-driven photoreactivity of [2,2]paracyclophane (PCP) ketoesters that enables site-selective hydrogen atom transfer (HAT) under visible-light irradiation. The PCP ketoester enables free-radical photopolymerization under air, deep curing, and low toxicity. In combination with an iodonium salt, a photooxidative SET mechanism takes place, allowing dual radical-cationic initiation and access to interpenetrating polymer networks. In the three-component PCP/iodonium/amine system, a photoredox catalytic mechanism significantly enhances polymerization rates. Upon excitation, PCP-based ketoesters undergo 1,5-HAT rather than the Norrish type-I pathway observed for conventional glyoxylates. Detailed spectroscopic, isotopic labeling, electron spin resonance (ESR) spin-trapping, and computational studies reveal that stabilization of the radical promotes a radical-polar crossover cascade cyclization. The HAT process is leveraged to develop metal-free photoinitiators that operate efficiently under 405 nm LED irradiation.
Visible-light-mediated electron donor-acceptor (EDA) complex catalysis has emerged as a powerful strategy for radical transformations under mild conditions, yet EDA donor catalytic systems driven by hydrogen bonding remain largely underexplored. Herein, we report a H-bonded EDA (H-EDA) donor catalysis system, employing...
Zhe Su, Ting-Tao Yan, Ke-Lu Yan et al.· Organic Letters· 0 citations
C–S bond formation via hydrogen atom transfer (HAT) remains underdeveloped despite the importance of thioethers in organic synthesis, materials science, and medicinal chemistry. Herein, we report a mild, rapid, and operationally simple method for the direct α-C(sp3)–S bond formation in ethers using alkyl or aryl thiosu...
Alexander Karr, Elias Picazo· ACS Omega· 0 citations
Hydroalkylation provides a direct approach to C(sp3)–C(sp3) bond formation from abundant alkenes, yet general methods for linear-selective hydroalkylation remain limited, particularly for simple alkyl groups such as methyl and ethyl. Here we introduce traceless radical polarity reversal, in which a removable electron-w...
Shih-Chieh Kao, Kang-Jie Bian, Jess C. Tang et al.· Nature Catalysis· 0 citations
Sulfinamides and related sulfur(VI) motifs are widely represented in bioactive molecules; however, their direct installation onto alkenes has traditionally relied on Lewis acid- or transition metal-mediated two-electron pathways, with more recent advances dominated by photoinduced single-electron processes. Here, we re...
The selective α-C(sp3)-H functionalization of amines has emerged as a valuable strategy for the rapid construction of structurally diverse and synthetically important amine architectures. Among the various approaches developed for α-amino radical generation, intramolecular radical translocation via hydrogen atom transf...
Vinjamuri Srinivasu, Kanak Ranjan Saha, Shalini Bagchi et al.· Chemical Communications· 0 citations
Nitrogen-containing molecules are ubiquitous in pharmaceuticals, agrochemicals, and functional materials, making the development of efficient C─N bond-forming reactions a central goal in synthesis. Cobalt-catalyzed metal-hydride hydrogen atom transfer (Co─H/MHAT) has emerged as a powerful platform for alkene hydroamina...
