Decatungstate-photocatalyzed transfer hydrogenation of unsaturated compounds using alcohol as the hydrogen source - Research Article

Sep 30, 2026

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A photocatalytic transfer hydrogenation strategy converts unsaturated compounds using alcohol as the hydrogen source and low-cost decatungstate as the catalyst. The method proceeds under mild, ambient conditions and shows broad scope across alkyl, aryl, and heteroatom-substituted alkenes/alkynes, azo compounds, and nitroarenes. Tungsten-based catalysis is reported as a first, delivering high chemoselectivity with selective hydrogenation of alkenes and alkynes even alongside ketones and carboxylic acids, supporting practical and sustainable organic synthesis.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages9

Reading Time23 min

AccessFree to download

Overview

Background: hydrogenation and alternative hydrogen sources

Photochemical strategies for alkene hydrogenation

Proposed approach

Alcohol as a sustainable transfer hydrogen source

Role of decatungstate and mechanistic rationale

Prior work context

Photocatalytic transfer hydrogenation via reduction or HAT

Scope and selectivity

Substrate compatibility and chemoselectivity

Article [https://doi.org/10.1038/s41467-025-67482-1](https://doi.org/10.1038/s41467-025-67482-1) Decatungstate-photocatalyzed transfer hydrogenation of unsaturated compounds using alcohol as the hydrogen source Received: 30 April 2025 | Accepted: 2 December 2025 | | --- | | | | Check for updates | Teng Zhang1, Zheng-Feng Zhang2, Xuan Lan3, Si-Yi Li3, Ming-Der Su 2,4 , Yonggui Robin Chi 1 , Lixin Wu 5 & Cheuk-Wai So 1 We present a simple and efﬁcient photocatalytic method for the transfer hydrogenation of unsaturated compounds using alcohol as the hydrogen source and low-cost decatungstate as the photocatalyst. Our approach operates under mild and ambient conditions and demonstrates broad substrate compatibility, including alkyl, aryl, and heteroatom-substituted alkenes, alkynes, azo compounds and nitroarenes. To our knowledge, this study represents the ﬁrst instance of using tungsten-based catalysts for the photocatalytic transfer hydrogenation of unsaturated compounds. Notably, the catalytic system, employing decatungstate as the catalyst and alcohol as the hydrogen source, exhibits high chemoselectivity, enabling selective hydrogenation of alkenes and alkynes even in the presence of reactive groups like ketones and carboxylic acids. These features highlight the considerable potential of this approach for practical and sustainable applications in organic synthesis. Hydrogenation of alkenes is one of the most fundamental transformations in organic synthesis, typically requiring both a catalyst and a hydrogen source1–19. The most common hydrogen source is hydrogen gas (H₂), known for its 100% atom efﬁciency. However, safety concerns related to handling ﬂammable and potentially explosive H₂ have led to the exploration of alternative hydrogen sources20–38. Photochemistry offers a novel approach for converting organic substrates into alternative hydrogen sources. One notable strategy involves photocatalytic reduction of alkenes to radical anions, which subsequently react with Brønsted-Lowry acids or solvents as proton donors to facilitate catalytic hydrogenation39. For instance, Guo and Houk et al. employed the strong acid TfOH and thioxanthone (TX) to photo-catalytically reduce α,β-unsaturated carbonyl compounds by using p-xylene (solvent) as the proton source (Fig. 1a)40. Similarly, Polyzos et al. described an iridium-catalyzed reduction of alkenes, followed by a reaction with Brønsted-Lowry acids to produce alkanes (Fig. 1b)41. However, this technique is limited by the reduction potential of the targeted alkenes. An alternative strategy was then developed, where iridium complexes were usually used to photo-catalytically generate radical cations to undergo hydrogen atom transfer (HAT) reactions with alkenes to form hydrogenadduct carbon radicals. This is followed by either protonation with a proton source or addition with a hydrogen radical source to achieve catalytic hydrogenation42–46. For example, Wenger et al. demonstrated that an iridium photocatalyst mediated the HAT reaction between triethylamine (TEA) and alkenes, with subsequent radical addition completing alkene hydrogenation (Fig. 1c)45. Moreover, Studer and coworkers developed an iridium-catalyzed system for generating phosphine radical cations that activated water molecules to form a PR₃–H₂O radical cation intermediate, effectively utilizing both hydrogen atoms from H₂O in the alkene hydrogenation through sequential heterolytic (H⁺) and homolytic (H•) O–H bond cleavages (Fig. 1d)46. Despite these advancements, replacing these rare and costly iridium photocatalysts with more abundant and 1School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, Singapore, Singapore. 2Department of Applied Chemistry, National Chiayi University, Chiayi, Taiwan. 3College of Chemistry and Materials Science, Zhejiang Normal University, Jinhua, China. 4Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohs

FAQs

What catalyst and hydrogen source are used in this photocatalytic transfer hydrogenation method?

Decatungstate acts as the photocatalyst, while alcohol serves as the hydrogen source for transferring hydrogen to unsaturated substrates.

Under what conditions does the decatungstate photocatalyzed reaction operate?

The approach is described as working under mild and ambient conditions.

How selective is the hydrogenation and what functional groups can be tolerated?

The catalytic system shows high chemoselectivity, enabling selective hydrogenation of alkenes and alkynes even in the presence of reactive ketones and carboxylic acids.

Sep 30, 2026

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