15982-59-9Relevant academic research and scientific papers
Oxovanadium(v)-catalyzed oxidative cross-coupling of enolates using O2as a terminal oxidant
Osafune, Yuma,Jin, Yuqing,Hirao, Toshikazu,Tobisu, Mamoru,Amaya, Toru
supporting information, p. 11697 - 11700 (2020/10/19)
The oxovanadium(v)-catalyzed oxidative cross-coupling of enolates using O2 as a terminal oxidant is reported, where a boron enolate and a silyl enol ether were employed as enolates. The redox behavior of V(v/iv) in this reaction under O2 was investigated by ESR and 51V NMR experiments.
Synthesis of 1,4-Dicarbonyl Compounds by Visible-Light-Mediated Cross-Coupling Reactions of α-Chlorocarbonyls and Enol Acetates
Liu, Qiang,Wang, Rui-Guo,Song, Hong-Jian,Liu, Yu-Xiu,Wang, Qing-Min
, p. 4391 - 4396 (2020/09/21)
Herein, we report a protocol for visible-light-mediated radical coupling reactions of α-chloroketones and enol acetates to afford 1,4-dicarbonyl compounds, which are important precursors and intermediates in organic synthesis. The reaction involves photoredox-catalyzed activation of the α-chloroketone upon photoelectron transfer, carbon–chlorine bond cleavage, and coupling of the resulting radical with the carbon–carbon double bond of the enol acetate. This mild protocol has a wide substrate scope and moderate to good yields. (Figure presented.).
Cross-coupling of dissimilar ketone enolates via enolonium species to afford non-symmetrical 1,4-diketones
Parida, Keshaba N.,Pathe, Gulab K.,Maksymenko, Shimon,Szpilman, Alex M.
, p. 992 - 997 (2019/12/23)
Due to their closely matched reactivity, the coupling of two dissimilar ketone enolates to form a 1,4-diketone remains a challenge in organic synthesis. We herein report that umpolung of a ketone trimethylsilyl enol ether (1 equiv) to form a discrete enol
Eosin Y as a Direct Hydrogen-Atom Transfer Photocatalyst for the Functionalization of C?H Bonds
Fan, Xuan-Zi,Rong, Jia-Wei,Wu, Hao-Lin,Zhou, Quan,Deng, Hong-Ping,Da Tan, Jin,Xue, Cheng-Wen,Wu, Li-Zhu,Tao, Hai-Rong,Wu, Jie
supporting information, p. 8514 - 8518 (2018/07/14)
Eosin Y, a well-known economical alternative to metal catalysts in visible-light-driven single-electron transfer-based organic transformations, can behave as an effective direct hydrogen-atom transfer catalyst for C?H activation. Using the alkylation of C?H bonds with electron-deficient alkenes as a model study revealed an extremely broad substrate scope, enabling easy access to a variety of important synthons. This eosin Y-based photocatalytic hydrogen-atom transfer strategy is promising for diverse functionalization of a wide range of native C?H bonds in a green and sustainable manner.
Selective intermolecular oxidative cross-coupling of enolates
Amaya, Toru,Maegawa, Yusuke,Masuda, Takaya,Osafune, Yuma,Hirao, Toshikazu
, p. 10072 - 10075 (2015/09/01)
Selective intermolecular oxidative cross-coupling of enolates, which is a bond-forming reaction between carbanion equivalents, remains as an unsolved issue despite its potential utility for the direct synthesis of unsymmetrical 1,4-diones. The main difficulty derives from the unavoidable homo-coupling. Our strategy depends on the selective one-electron oxidation of one enolate to afford an electrophilic carbonyl α-radical species, followed by trapping with another enolate. The present study demonstrates the selective oxovanadium(V)-induced cross-coupling between boron and silyl enolates.
Radical alkylations of alkyl halides and unactivated C-H bonds using vinyl triflates
Lee, Jin Young,Lim, Kyoung-Chan,Meng, Xiangjian,Kim, Sunggak
experimental part, p. 1647 - 1650 (2010/09/04)
Radical alkylations of activated alkyl iodides and bromides were achieved using vinyl triflates in the presence of hexadimethyltin, whereas those of unactivated C-H bonds using vinyl triflates proceeded cleanly under tin-free conditions. Georg Thieme Verl
Ring-opening of tertiary cyclopropanols derived from β-diketones
Li, Le-Zhen,Xiao, Bin,Guo, Qing-Xiang,Xue, Song
, p. 7762 - 7771 (2007/10/03)
The ring-opening reaction of 1,2-disubstituted cyclopropanols, prepared from β-diketones, mediated by Cu(NO3)2, p-TsOH, and NaOH is reported. The Cu(II)-mediated ring-opening of cyclopropanols gave α-methylene-γ-diketones in good yie
Free radical ring expansion and chain extension of 1,3-diketones
Mu, Xue-Jun,Zou, Jian-Ping,Wang, Zhi-Tao,Zhang, Wei
, p. 4727 - 4729 (2007/10/03)
Free radical-promoted one carbon ring expansion and chain extension of 1,3-diketones including 1,3-diarylpropane-1,3-diones and 2-aroyl-3,4-dihydro-2H- naphalen-1-one to generate corresponding 1,4-diketones are described.
Cross-coupling reaction of α-chloroketones and organotin enolates catalyzed by zinc halides for synthesis of γ-diketones
Yasuda, Makoto,Tsuji, Shoki,Shigeyoshi, Yusuke,Baba, Akio
, p. 7440 - 7447 (2007/10/03)
The reaction of tin enolates 1 with α-chloro- or bromoketones 2 gave γ-diketones (1,4-diketones) 3 catalyzed by zinc halides. In contrast to the exclusive formation of 1,4-diketones 3 under catalytic conditions, uncatalyzed reaction of 1 with 2 gave aldol-type products 4 through carbonyl attack. NMR study indicates that the catalyzed reaction includes precondensation between tin enolates and α-haloketones providing an aldol-type species and their rearrangement of the oxoalkyl group with leaving halogen to produce 1,4-diketones. The catalyst, zinc halides, plays an important role in each step. The carbonyl attack for precondensation is accelerated by the catalyst as Lewis acid and the intermediate zincate promotes the rearrangement by releasing oxygen and bonding with halogen. Various types of tin enolates and α-chloro and bromoketones were applied to the zinc-catalyzed cross-coupling. On the other hand, the allylic halides, which have no carbonyl moiety, were inert to the zinc-catalyzed coupling with tin enolates. The copper halides showed high catalytic activity for the coupling between tin enolates 1 and organic halides 7 to give γ,δ-unsaturated ketones 8 and/or 9. The reaction with even chlorides proceeded effectively by the catalytic system.
