Henri Boris Kagan (born 15 December 1930, Boulogne-Billancourt, France) is a French organic chemist known for pioneering research in asymmetric catalysis and the use of lanthanide compounds in organic synthesis. His principal contributions include the development of the chiral ligand DIOP, the investigation of nonlinear effects in asymmetric synthesis, and practical methods for using samarium(II) iodide. He shared the 2026 Nobel Prize in Chemistry with Kenso Soai for discoveries concerning nonlinear effects and autocatalysis in asymmetric organic synthesis. (academie-sciences.fr)
Education and academic career
Kagan graduated from the École nationale supérieure de chimie de Paris and obtained a science degree from the Sorbonne in 1954. He began his research career at the French National Centre for Scientific Research that year and completed a doctorate in 1960, with research supervised by Jean Jacques at the Collège de France. His subsequent training included a postdoctoral stay at the University of Texas at Austin. (cths.fr)
His academic career became closely associated with Orsay and the University of Paris-Sud, now part of Paris-Saclay University. He was appointed maître de conférences in 1967 and became a full professor in 1973. He was elected a corresponding member of the French Academy of Sciences in 1978 and a full member on 8 April 1991. (ac-reunion.fr)
Asymmetric catalysis and DIOP
Asymmetric catalysis concerns reactions in which a catalyst favors the formation of one enantiomer over its mirror-image counterpart. Kagan’s work helped demonstrate how the structure of a metal-bound ligand could control this selectivity. Such control is important in preparing compounds with a specified molecular handedness, including pharmaceutical intermediates and fine chemicals. (wolffund.org.il)
In 1971, Kagan reported the use of DIOP, a chiral ligand with symmetry, in rhodium-catalyzed asymmetric hydrogenation. The resulting preference for one product enantiomer made DIOP an influential example of deliberate ligand design. Its significance extended beyond a single reaction: it encouraged the development of other -symmetric ligands and research into asymmetric hydrogenation, hydroformylation, hydrosilylation, and allylic alkylation. (wolffund.org.il)
Nonlinear effects in asymmetric synthesis
In 1986, Kagan and collaborators reported nonlinear effects in asymmetric synthesis, with examples involving asymmetric oxidations and aldol reactions. These observations challenged the assumption that the enantiomeric composition of a chiral catalyst or reagent would necessarily translate proportionally into the enantiomeric composition of the product. (pubmed.ncbi.nlm.nih.gov)
Kagan subsequently developed simplified mathematical models to describe such behavior. Nonlinear effects became a means of investigating the molecular mechanisms of asymmetric reactions; asymmetric amplification also connected this research to questions about the emergence of biological chirality. These applications distinguish the work from the development of individual synthetic procedures: it supplied a framework for examining how chiral components interact within a reacting system. (academie-sciences.fr)
Samarium reagents
A separate strand of Kagan’s research concerned samarium(II) iodide, . In a 1980 paper, Philippe Girard, Jean-Louis Namy, and Kagan described convenient preparations of samarium and ytterbium diiodides in tetrahydrofuran and investigated their use as reducing and coupling agents. Their experiments included selective reductions, deoxygenation reactions, and reactions joining organic halides with carbonyl compounds. This work provided practical access to reagents for transformations distinct from his asymmetric metal-catalysis research. (electronicsandbooks.com)
Recognition
Kagan shared the 2001 Wolf Prize in Chemistry with Ryoji Noyori and K. Barry Sharpless for contributions to asymmetric catalysis. On 7 October 2026, the Nobel Prize in Chemistry was announced jointly for Kagan and Soai, recognizing their discoveries of nonlinear effects and autocatalysis in asymmetric organic synthesis. (wolffund.org.il)
References
- Henri Kagan | Académie des sciencesacademie-sciences.fr
- CTHS - KAGAN Henri Boriscths.fr
- Henri B. Kagan - Wolf Foundationwolffund.org.il
- Henri Kagan membre de l'Académie des sciences et Kenso Soai, lauréats du prix Nobel de chimie 2026academie-sciences.fr