80221-01-8Relevant articles and documents
Cobalt-Catalyzed Chemo- and Enantioselective Hydrogenation of Conjugated Enynes
Hu, Yanhua,Liu, Yangang,Zhang, Wanbin,Zhang, Zhenfeng
, p. 16989 - 16993 (2021/06/28)
Asymmetric hydrogenation is one of the most powerful methods for the preparation of single enantiomer compounds. However, the chemo- and enantioselective hydrogenation of the relatively inert unsaturated group in substrates possessing multiple unsaturated bonds remains a challenge. We herein report a protocol for the highly chemo- and enantioselective hydrogenation of conjugated enynes while keeping the alkynyl bond intact. Mechanism studies indicate that the accompanying Zn2+ generated from zinc reduction of the CoII complex plays a critical role to initiate a plausible CoI/CoIII catalytic cycle. This approach allows for the highly efficient generation of chiral propargylamines (up to 99.9 % ee and 2000 S/C) and further useful chemical transformations.
Bisphosphine catalyzed sequential [3 + 2] cycloaddition and Michael addition of ynones with benzylidenepyrazolones: Via dual α′,α′-C(sp3)-H bifunctionalization to construct cyclopentanone-fused spiro-pyrazolones
Zhang, Jiayong,Miao, Zhiwei
supporting information, p. 9461 - 9471 (2019/01/03)
A bisphosphine-catalyzed sequential [3 + 2] cycloaddition and Michael addition reaction of ynones with benzylidenepyrazolones has been developed. Under the catalysis of DPPB [1,4-bis(diphenylphosphino)butane], the reaction proceeded smoothly to give spiro-[cyclopentanone] pyrazolone derivatives in moderate to good yields with good diastereoselectivities via sequential dual α′,α′-C(sp3)-H bifunctionalization annulation. This strategy provides a novel route toward the synthesis of spiro-[cyclopentanone] pyrazolones containing three contiguous stereocenters which possess potential pharmaceutical activities.
