Iridium(I) versus Ruthenium(II). A Computational Study of the Transition Metal Catalyzed Transfer Hydrogenation of Ketones

• DOI: 10.1021/om030104t
• Publication Date: 2003-07-14T09:58:03Z
• Authors: Jan-Willem Handgraaf; Joost N. H. Reek; Evert Jan Meijer
• Keywords: Transfer hydrogenation; Noyori asymmetric hydrogenation; Alkoxide; Transition state

We present a density functional theory based computational study comparing simplified models for the ruthenium(II)- and iridium(I)-catalyzed transfer hydrogenation of ketones. For ruthenium compound our results confirm earlier findings that involves hydride occurs via concerted hydrogen mechanism with no direct ruthenium−ketone binding along reaction path. In contrast, iridium calculations suggest proceeds between simultaneously coordinated ketone alcohol. find both metal complexes formation very stable metal−alkoxide complex plays an important role. ruthenium-catalyzed it constitutes resting state does not take active part in hydrogenation, while iridium-catalyzed is intermediate