1447423-17-7Relevant academic research and scientific papers
Diboron-mediated palladium-catalyzed asymmetric transfer hydrogenation using the proton of alcohols as hydrogen source
Wu, Bo,Yang, Jimin,Hu, Shu-Bo,Yu, Chang-Bin,Zhao, Zi-Biao,Luo, Yi,Zhou, Yong-Gui
, p. 1743 - 1749 (2021/09/06)
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. [Figure not available: see fulltext.]
Enantioselective hydrogenation of N-heteroaromatics catalyzed by chiral diphosphine modified binaphthyl palladium nanoparticles
Xia, Yun-Tao,Ma, Jing,Wang, Xiao-Dong,Yang, Lei,Wu, Lei
, p. 5515 - 5520 (2017/12/07)
The first application of binaphthyl-stabilized palladium nanoparticles (Bin-PdNPs) with chiral modifiers in asymmetric hydrogenation of N-heteroaromatics is revealed. With an appropriate ratio of R-BINAP/Bin-PdNPs used, the pre-prepared chiral nanocatalyst achieves asymmetric hydrogenations of 2-substituted quinolines with good to excellent yields and moderate enantioselectivities, which showed superior catalytic properties to the R-BINAP/Pd complex. Moreover, this protocol is also applicable to 2-substituted indoles.
Highly enantioselective hydrogenation of N-unprotected indoles using (S)-C10-BridgePHOS as the chiral ligand
Li, Chao,Chen, Jianzhong,Fu, Guanghong,Liu, Delong,Liu, Yangang,Zhang, Wanbin
, p. 6839 - 6844 (2013/07/26)
(S)-C10-BridgePHOS was successfully applied to a highly efficient Pd-catalyzed enantioselective hydrogenation of substituted indoles. The methodology was suitable for the hydrogenation of indoles substituted at the 2-, 3- and 2,3-positions. Products were obtained in quantitative conversion and up to 98% ee. The role the 2-position substituent plays in the hydrogenation process has been proposed. The methodology could be used as an alternative method to synthesize extremely important chiral indolines from N-unprotected indoles.
