The Effect of Conformational Freedom vs Restriction on the Rate in Asymmetric Hydrogenation: Iridium-Catalyzed Regio- and Enantioselective Monohydrogenation of DienonesShow others and affiliations
2024 (English)In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 30, no 13, article id e202303406Article in journal (Refereed) Published
Abstract [en]
Transition metal-catalyzed asymmetric hydrogenation constitutes an efficient strategy for the preparation of chiral molecules. When dienes are subjected to hydrogenation, control over regioselectivity still presents a large challenge and the fully saturated alkane is often yielded. A few successful monohydrogenations of dienes have been reported, but hitherto these are only efficient for dienes comprised of two distinctly different olefins. Herein, the reactivity of a conjugated carbonyl compound as a function of their conformational freedom is studied, based on a combined experimental and theoretical approach. It was found that alkenes in the (s)-cis conformation experience a large rate acceleration while (s)-trans restrained alkenes undergo hydrogenation slowly. Ultimately, this reactivity aspect was exploited in a novel method for the monohydrogenation of dienes based on conformational restriction ((s)-cis vs (s)-trans). This mode of discrimination conceptually differs from existing monohydrogenations and dienones constructed of two olefins similar in nature could efficiently be hydrogenated to the chiral alkene (up to 99 % ee). The extent of regioselection is even powerful enough to overcome the conventional reactivity order of substituted olefins (di>tri>tetra). This high yielding and atom-economical protocol provides an interesting opportunity to instal a stereogenic center on a carbocycle, while leaving a synthetically useful alkene untouched.
Place, publisher, year, edition, pages
Wiley , 2024. Vol. 30, no 13, article id e202303406
Keywords [en]
Dienes, Hydrogenation, Iridium catalysis, Monohydrogenation, Regioselectivity
National Category
Organic Chemistry
Identifiers
URN: urn:nbn:se:kth:diva-367100DOI: 10.1002/chem.202303406ISI: 001141775100001PubMedID: 38109038Scopus ID: 2-s2.0-85182158565OAI: oai:DiVA.org:kth-367100DiVA, id: diva2:1984223
Note
QC 20250715
2025-07-152025-07-152025-07-15Bibliographically approved