80221-02-9Relevant academic research and scientific papers
Cobalt-Catalyzed Chemo- and Enantioselective Hydrogenation of Conjugated Enynes
Hu, Yanhua,Liu, Yangang,Zhang, Wanbin,Zhang, Zhenfeng
supporting information, 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.
Synthesis of substituted benzo[: B] [1,4]oxazepine derivatives by the reaction of 2-aminophenols with alkynones
Oshimoto, Kohei,Zhou, Biao,Tsuji, Hiroaki,Kawatsura, Motoi
supporting information, p. 415 - 419 (2020/01/30)
We have developed a novel synthetic method accessing benzo[b][1,4]oxazepines that are one of the rare classes of benzoxazepine derivatives by reaction of 2-aminophenols with alkynones in 1,4-dioxane at 100 °C. A series of benzo[b][1,4]oxazepine derivatives can be prepared by using this synthetic protocol. Mechanistic experiments indicated that the hydroxy proton of the aminophenol could play a crucial role in the formation of an alkynylketimine intermediate that undergoes 7-endo-dig cyclization.
Phosphine-Catalyzed Intermolecular Annulations of Fluorinated ortho-Aminophenones with Alkynones – The Switchable [4+2] or [4+2]/[3+2] Cycloaddition
Zhang, Yanshun,Sun, Yaoliang,Wei, Yin,Shi, Min
supporting information, p. 2129 - 2135 (2019/03/13)
A phosphine-catalyzed intermolecular annulation reaction of functionalized ortho-aminoacetophenones with alkynones has been disclosed in this paper. A variety of 2-alkynylquinolines and benzo-fused indolizine were selectively afforded in moderate to good yields at different reaction temperatures and with different phosphine catalysts via the in situ generated zwitterionic intermediate derived from alkynone and phosphine. (Figure presented.).
Multicomponent Oxidative Trifluoromethylation of Alkynes with Photoredox Catalysis: Synthesis of α-Trifluoromethyl Ketones
Malpani, Yashwardhan R.,Biswas, Bishyajit Kumar,Han, Hong Sik,Jung, Young-Sik,Han, Soo Bong
supporting information, p. 1693 - 1697 (2018/04/16)
The direct oxidative addition of CF3 and H2O to alkynes was achieved with photoredox catalysis to obtain α-trifluoromethyl ketones via rapid enol-keto tautomerization. The reaction exhibits high functional group tolerance and regioselectivity. Heterocycles of various sizes containing CF3 were synthesized from the α-CF3-substituted diketones obtained through the protocol, thereby demonstrating the versatile applicability of the method. Mechanistic studies of the reaction with isotopes provided insight into the reaction pathway.
Gold-catalyzed N,O-functionalization of 1,4-diyn-3-ols with: N -hydroxyanilines to form highly functionalized pyrrole derivatives
Hsu, Yu-Chen,Hsieh, Shu-An,Li, Po-Hsuan,Liu, Rai-Shung
supporting information, p. 2114 - 2117 (2018/03/06)
This work describes new N,O-functionalization of 1,4-diyn-3-ols with N-hydroxyanilines to yield highly functionalized pyrrole derivatives. In a postulated mechanism, N-hydroxyaniline attacks the more electron-rich alkynes via regioselective N-attack to form unstable ketone-derived nitrones that react with their tethered alkynes via an intramolecular oxygen-transfer to form α-oxo gold carbenes. This new method is applicable to a short synthesis of a bioactive molecule, a PDE4 inhibitor.
Iridium-Catalyzed Asymmetric Transfer Hydrogenation of Alkynyl Ketones Using Sodium Formate and Ethanol as Hydrogen Sources
Zhang, Yang-Ming,Yuan, Ming-Lei,Liu, Wei-Peng,Xie, Jian-Hua,Zhou, Qi-Lin
supporting information, p. 4486 - 4489 (2018/08/09)
A green and efficient iridium-catalyzed asymmetric transfer hydrogenation of alkynyl ketones to chiral propargylic alcohols has been developed. By using sodium formate and ethanol as hydrogen sources, a series of alkynyl ketones were hydrogenated by chira
Highly efficient synthesis of benzodioxins with a 2-site quaternary carbon structure by secondary amine-catalyzed dual Michael cascade reactions
He, Xuefeng,Li, Yongsu,Wang, Meng,Chen, Hui-Xuan,Chen, Bin,Liang, Hao,Zhang, Yaqi,Pang, Jiyan,Qiu, Liqin
supporting information, p. 5533 - 5538 (2018/08/12)
Salicylic acids and substituted ynones were employed as substrates to afford a class of valuable 4H-benzo[d][1,3]dioxin-4-ones with a 2-site quaternary carbon structure in up to 92% yield by secondary amine-catalyzed dual Michael cascade reactions under mild reaction conditions. The α,β-unsaturated ketone as the key intermediate in the cascade process was successfully separated and characterized. As a result, a new reaction route for ynone species is demonstrated, which is totally different from the existing allenamine activation model.
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.
Selective Carbonyl?C(sp3) Bond Cleavage To Construct Ynamides, Ynoates, and Ynones by Photoredox Catalysis
Jia, Kunfang,Pan, Yue,Chen, Yiyun
supporting information, p. 2478 - 2481 (2017/02/23)
Carbon–carbon bond cleavage/functionalization is synthetically valuable, and selective carbonyl?C(sp3) bond cleavage/alkynylation presents a new perspective in constructing ynamides, ynoates, and ynones. Reported here is the first alkoxyl-radical-enabled carbonyl?C(sp3) bond cleavage/alkynylation reaction by photoredox catalysis. The use of novel cyclic iodine(III) reagents are essential for β-carbonyl alkoxyl radical generation from β-carbonyl alcohols, including alcohols with high redox potential (EoxP>2.2 V vs. SCE in MeCN). β-Amide, β-ester, and β-ketone alcohols yield ynamides, ynoates, and ynones, respectively, for the first time, with excellent regio- and chemoselectivity under mild reaction conditions.
