Diboron-mediated palladium-catalyzed asymmetric transfer hydrogenation using the proton of alcohols as hydrogen source

Autor: Bo Wu, Zi-Biao Zhao, Yi Luo, Jimin Yang, Shu-Bo Hu, Changbin Yu, Yong-Gui Zhou
Rok vydání: 2021
Předmět:
Zdroj: Science China Chemistry. 64:1743-1749
ISSN: 1869-1870
1674-7291
DOI: 10.1007/s11426-021-1049-9
Popis: The developments of hydrogen sources stand at the forefront of asymmetric reduction. In contrast to the well-studied alcohols as hydrogen sources via β-hydride elimination, the direct utilization of the proton of alcohols as a hydrogen source for activator-mediated asymmetric reduction is rarely explored. Herein we report the proton of alcohols as a hydrogen source in diboron-mediated palladium-catalyzed asymmetric transfer hydrogenation of 1,3-diketones and indoles, providing a series of chiral β-hydroxy ketones and indolines with excellent yields and enantioselectivities. This strategy would be useful for the synthesis of chiral deuterium-labelled compounds due to the ready availability of deuterium-labelled alcohols. Mechanistic investigations and DFT calculations revealed that active chiral Pd-H species was generated from the proton of alcohols by activating of tetrahydroxydiboron, hydrogen transfer was the rate-determining step, and the reaction preferred Pd(0)-catalyzed mechanism.
Databáze: OpenAIRE
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