A team led by Abigail Doyle<\/a> at the University of California, Los Angeles, found that phosphines can show transition- metal-like reactivity in a light-driven reaction<\/a> between amine-containing rings and carbon-carbon double bonds (Nature 2026, DOI: 10.1038\/s41586-026-10263-7).<\/p>\n \u201cThis project adds to the growing body of literature that showcases the unique reactivity of main group compounds as catalysts and the resulting opportunities for organic synthesis,\u201d Doyle says in an email to C&EN.<\/p>\n \u201cIt\u2019s kind of just rethinking what these compounds can do and their role in chemistry,\u201d says Flora Fan, a fourth-year graduate student in Doyle\u2019s lab who did much of the hands-on work.<\/p>\n Phosphine catalysts can help chemists access reactivity that transition metals may struggle with, such as hydroamination with nitrogen-rich rings and terminal alkenes.<\/p>\n The new paper builds on a previous study the group published describing a way to use a phosphine and an iridium photocatalyst to facilitate an addition reaction between alkenes and azoles<\/a> (J. Am. Chem. Soc. 2024, DOI: 10.1021\/jacs.4c05881). Kassandra Sedillo, who worked on the project as a graduate student, noticed that when she used a triphenylphosphine derivative instead of tricyclohexylphosphine, the amine attached to the more substituted alkene carbon rather than the less substituted one. That selectivity switch indicated that the mechanism had changed from the expected nitrogen-radical route to something else.<\/p>\n \u201cWe couldn\u2019t explain through our proposed mechanism how we were obtaining that product,\u201d Fan says, so she started investigating how it might have formed.<\/p>\n From competition experiments and density functional theory computations, Fan figured out that the phosphine radical generated by the photocatalyst was coordinating to the alkene\u2014much like a metal would\u2014to create a spatially separated radical cation intermediate. This intermediate then adds to the amine through one of two potential pathways; Fan says both could be occurring at once. A thiol furnishes the molecule with a nitrogen to give the final product.<\/p>\n \u201cIt\u2019s a very atom-economical reaction. You\u2019re not generating any by-products. Everything is catalytic. So all the atoms are used,\u201d Fan says. She and her lab mates found that the reaction can handle a variety of aromatic and nonaromatic heterocycles, and it even works if other potentially reactive functional groups, such as alcohols, are present.<\/p>\n Sami Lakhdar<\/a>, who researches photocatalysis at the University of Toulouse and was not involved in the work, calls it \u201creally spectacular\u201d and \u201ca breakthrough in the field of main-group catalysis.\u201d The overall transformation is something that isn\u2019t accessible with transition metals, he adds, so it\u2019s practical as well as conceptually interesting.<\/p>\n![\"A](\"https:\/\/www.newsbeep.com\/ie\/wp-content\/uploads\/2026\/03\/science-news--phosphine-photocatalysis---375849.jpg\")
\n A reaction scheme showing a pyrazole derivative adding to a terminal alkene.<\/p>\n
![\"\"](\"https:\/\/www.newsbeep.com\/ie\/wp-content\/uploads\/2025\/10\/2025-bri.jpg\")
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