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Updated: May 16, 2026
12:19
Photogeneration of N-Heterocyclic Carbenes: Application in Photoinduced Ring-Opening Metathesis Polymerization
Published on: November 29, 2018
Energy transfer (EnT)-mediated [2 + 2] photocycloadditions.
1Department of Chemistry, Rishi Bankim Chandra College for Women, Naihati, 24-Parganas (N), 743165, India. suvenchem@yahoo.co.in.
Organic & Biomolecular Chemistry
|May 14, 2026
Summary
Visible light-mediated triplet energy transfer (EnT) enables efficient [2 + 2] cycloadditions for constructing cyclobutane scaffolds. This review covers recent advances in inter- and intramolecular reactions, offering sustainable synthetic strategies.
Area of Science:
- Organic Chemistry
- Photochemistry
- Sustainable Synthesis
Background:
- [2 + 2] cycloadditions are traditionally UV-driven and energy-intensive.
- Triplet energy transfer (EnT) offers a milder alternative using visible light.
- Cyclobutane scaffolds are valuable structural motifs in organic chemistry.
Purpose of the Study:
- To review recent advances (2022-2025) in energy-transfer mediated [2 + 2] photocycloadditions.
- To highlight efficient strategies for constructing cyclobutane frameworks.
- To discuss mechanistic aspects of these transformations.
Main Methods:
- Focus on visible light-mediated triplet energy transfer (EnT).
- Categorization of intermolecular reactions: alkene-alkene, alkene-heterocycle, and aza-/thia-Paternò-Büchi.
- Subdivision of intramolecular reactions: involving heterocycles, carbocycles, and acyclic analogues.
- Discussion of EnT-mediated [2π + 2σ] cycloadditions.
Main Results:
- Demonstration of mild, selective, and sustainable access to cyclobutane scaffolds.
- Expansion of reaction scope to include diverse olefinic substrates.
- Exploration of new activation strategies for strained substrates via [2π + 2σ] cycloadditions.
Conclusions:
- Energy-transfer mediated [2 + 2] cycloadditions represent a significant advancement in synthetic organic chemistry.
- These methods provide sustainable and efficient routes to complex cyclobutane structures.
- Future directions include activating challenging substrates and expanding reaction diversity.
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