Vidar Remi Jensen is a Professor of Chemistry at the University of Bergen, Norway. He is a leading computational chemist specializing in automated, de novo molecular design, pioneering Big Computing / Big Data strategies for catalyst and material discovery. He focuses on developing general-purpose computational methods to predict and optimize molecular functions, integrating mechanistic insights with in silico design to bridge theory with experiment. He has published over 90 peer-reviewed articles and holds three US patents.

Lecture title:

Site isolation without immobilization: Toward high-productivity olefin metathesis catalysts

Olefin metathesis is the most versatile method known for the construction and manipulation of carbon-based frameworks. Moreover, with an unmatched atom economy, a scope that spans across chemistry and chemical biology, and benign reaction conditions, olefin metathesis holds enormous potential in sustainable chemical manufacturing. Despite its potential, this reaction is notorious for the severe problems arising from catalyst decomposition, which restrict both productivity and selectivity, and indeed industrial uptake.[1–3] Catalysts resistant to decomposition would eliminate the chief obstacle to implementation of metathesis in the industrial context, with major implications for utilization of renewable feedstocks, and production of specialty chemicals and active pharmaceutical ingredients.

A key intrinsic decomposition reaction in metathesis as well as in homogeneous catalysis more generally is bimolecular coupling.[2,3] Classically, bimolecular decomposition is addressed by site-isolation of molecular catalysts on solid supports. However, within the context of olefin metathesis, this approach has failed, in part because mass transfer restrictions compromise activity.[4,5] Here, we describe a new strategy for site-isolation that inhibits bimolecular coupling without recourse to immobilization (Figure 1).

References

1. Occhipinti, G.; Nascimento, D. L.; Foscato, M.; Fogg, D. E.; Jensen, V. R. The Janus face of high trans-effect carbenes in olefin metathesis: gateway to both productivity and decomposition. Chem. Sci. 2022, 13, 5107–5117. DOI: 10.1039/d2sc00855f.
2. Nascimento, D. L.; Foscato, M.; Occhipinti, G.; Jensen, V. R.; Fogg, D. E. Bimolecular Coupling in Olefin Metathesis: Correlating Structure and Decomposition for Leading and Emerging Ruthenium-Carbene Catalysts. J. Am. Chem. Soc. 2021, 143, 11072–11079. DOI: 10.1021/jacs.1c04424.
3. Engel, J.; Smit, W.; Foscato, M.; Occhipinti, G.; Törnroos, K. W.; Jensen, V. R. Loss and Reformation of Ruthenium Alkylidene: Connecting Olefin Metathesis, Catalyst Deactivation, Regeneration, and Isomerization. J. Am. Chem. Soc. 2017, 139, 16609–16619; DOI: 10.1021/jacs.7b07694.
4. Allen, D. P.; Van Wingerden, M. M.; Grubbs, R. H. Well-Defined Silica-Supported Olefin Metathesis Catalysts. Org. Lett. 2009, 11, 6, 1261–1264. DOI: 10.1021/ol9000153.
5. Hübner, S.; de Vries, J. G.; Farina, V. Why Does Industry Not Use Immobilized Transition Metal Complexes as Catalysts? Adv. Synth. Catal. 2016, 358, 3–25. DOI: 10.1002/adsc.201500846.