Work

A Redox‐Neutral Organophotocatalytic Cascade: Difluoromethylation and Radical Truce–Smiles ‐Driven C( sp 3 )–H Functionalization to Access Benzothiazine Dioxides and Oxindoles

Year: 2025

Type: article

Abstract: A new photochemical approach has been developed that enables the simultaneous difluoromethylation and radical cascade cyclization of alkenes, providing rapid and efficient access to structurally intricate 1,2‐benzothiazine dioxide derivatives. Importantly, strategic substrate modification expands the utility of this platform to an unprecedented distal ‘ Radical Truce‐Smiles rearrangement ’ enabled by a 1,5‐hydrogen atom transfer mechanism. This C( sp 3 )–H activation pathway overcomes conventional proximity constraints, allowing for the streamlined synthesis of valuable oxindole frameworks with high selectivity. The organophotocatalyst 4DPNIPN catalyzes the transformation and proceeds via a radical‐polar crossover mechanism initiated through oxidative luminescence quenching. Remarkably, the reaction operates under redox‐neutral conditions, eliminating the need for transition metals, stoichiometric oxidants, or external additives. This sustainable protocol exhibits broad functional group compatibility, operational simplicity, and scalability.

Source: Advanced Synthesis & Catalysis

DOI: 10.1002/adsc.70167

Authors: Koustav Pal, Aliya V. Jinilkumar, Manasi Mallick, Shirshendu Giri, Devarajulu Sureshkumar

Institution: Indian Institute of Science Education and Research Kolkata

Language: English

Topic: Radical Photochemical Reactions

Subfield: Organic Chemistry

Field: Chemistry

Domain: Physical Sciences

Open Access status: bronze

Funders: Department of Science and Technology, Ministry of Science and Technology, India, Indian Institute of Science Education and Research Mohali, Indian Institute of Science Education and Research Kolkata, Science and Engineering Research Board

OpenAlex ID: W4415313442

FWCI: 0.298

Cites: 58

Cited by: 1

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