Mechanism-based enantiodivergence in manganese reduction catalysis

• Verfasst von: Vasilenko, Vladislav [VerfasserIn]
• Verfasst von: Blasius, Clemens K. [VerfasserIn]
• Verfasst von: Wadepohl, Hubert [VerfasserIn]
• Verfasst von: Gade, Lutz H. [VerfasserIn]
• Titel: Mechanism-based enantiodivergence in manganese reduction catalysis
• Titelzusatz: a chiral pincer complex for the highly enantioselective hydroboration of ketones
• Verf.angabe: Vladislav Vasilenko, Clemens K. Blasius, Hubert Wadepohl, and Lutz H. Gade
• E-Jahr: 2017
• Jahr: 24 May 2017
• Umfang: 5 S.
• Fussnoten: Gesehen am 26.09.2018
• Titel Quelle: Enthalten in: Angewandte Chemie / International edition
• Ort Quelle: Weinheim : Wiley-VCH, 1962
• Jahr Quelle: 2017
• Band/Heft Quelle: 56(2017), 29, Seite 8393-8397
• ISSN Quelle: 1521-3773
• DOI: doi:10.1002/anie.201704184
• Datenträger: Online-Ressource
• Sprache: eng
• Sach-SW: enantioselectivity
• Sach-SW: hydroboration
• Sach-SW: manganese
• Sach-SW: reaction mechanisms
• Sach-SW: reduction
• K10plus-PPN: 1581308310

Abstract

A manganese alkyl complex containing a chiral bis(oxazolinyl-methylidene)isoindoline pincer ligand is a precatalyst for a catalytic system of unprecedented activity and selectivity in the enantioselective hydroboration of ketones, thus producing preparatively useful chiral alcohols in excellent yields with up to greater than 99 % ee. It is applicable for both aryl alkyl and dialkyl ketone reduction under mild reaction conditions (TOF >450 h−1 at −40 °C). The earth-abundant base-metal catalyst operates at very low catalyst loadings (as low as 0.1 mol %) and with a high level of functional-group tolerance. There is evidence for the existence of two distinct mechanistic pathways for manganese-catalyzed hydride transfer and their role for enantiocontrol in the selectivity-determining step is presented.