- Enantioselective [4 + 2] cycloaddition of cyclic N-sulfimines and acyclic enones or ynones: A concise route to sulfamidate-fused 2,6-disubstituted piperidin-4-ones
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A concise route to valuable sulfamate-fused 2,6-disubstituted piperidin-4-ones or 2,3-dihydropyridin-4(1H)-ones in good yield with high diastereo- and enantioselectivity is presented. The combination of chiral primary amine and o-fluorobenzoic acid efficiently promoted an asymmetric [4 + 2] cycloaddition reaction of N-sulfonylimines and enones or ynones. The cycloaddition reaction between cyclic N-sulfonylimines and ynones is first reported.
- Liu, Yong,Kang, Tai-Ran,Liu, Quan-Zhong,Chen, Lian-Mei,Wang, Ya-Chuan,Liu, Jie,Xie, Yong-Mei,Yang, Jin-Liang,He, Long
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Read Online
- A 2-heptanone synthetic method
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The invention discloses a chemical synthetic method, specifically a method for synthesizing 2-heptanone by using acetone and butyraldehyde as raw materials. According to the invention, acetone and butyraldehyde which used as raw materials undergo a cross aldol condensation reaction under catalysis of solid base, and reaction products further undergo dehydration and catalytic hydrogenation so as to prepare 2-heptanone. The invention has advantages as follows: technological process is shortened by the technology; generation of an acid-containing waste liquid is avoided; generation of by-products is minimized; investment in equipment is reduced; and production costs of the product are decreased.
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Paragraph 0043
(2017/01/26)
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- Activation of Chiral (Salen)AlCl Complex by Phosphorane for Highly Enantioselective Cyanosilylation of Ketones and Enones
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Phosphoranes 2 are identified as a class of effective Lewis bases to activate chiral (salen)AlCl complex 1 to enhance its electrophilicity. Accordingly, a three-component catalyst system consisting of complex 1, phosphorane 2e, and Ph3PO is developed as a powerful tool for asymmetric ketone cyanosilylation. In particular, an unprecedented highly enantioselective cyanosilylation of linear aliphatic ketones is achieved. A tandem Wittig-cyanosilylation sequence starting from phosphorane 2a and enals 10 is further achieved, which internally utilizes the Ph3PO byproduct and remaining phosphorane 2a as cocatalysts for cyanosilylation of α,β,γ,δ-unsaturated enones, providing atom-efficient access to valuable chiral conjugated dienes and enynes. The high efficiency of the cyanosilylation originates from orthogonal activation of both (salen)AlCl complex 1 and cyanotrimethylsilane by the phosphorane and Ph3PO, respectively. This mechanistic insight is supported by NMR, MS, and ReactIR analyses and DFT calculations. Furthermore, the formation of charged complexes through the activation of chiral complex 1 by phosphorane 2a is confirmed by electrical conductivity experiments.
- Zeng, Xing-Ping,Cao, Zhong-Yan,Wang, Xin,Chen, Long,Zhou, Feng,Zhu, Feng,Wang, Cui-Hong,Zhou, Jian
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supporting information
p. 416 - 425
(2016/01/25)
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- Processes for preparing beta-hydroxy-ketones and alpha,beta-unsaturated ketones
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Processes for producing β-hydroxy-ketones and α,β-unsaturated ketones are disclosed which comprise the crossed condensation of an aldehyde with a ketone in the presence of a hydroxide or alkoxide of alkali metal or an alkaline earth metal as catalyst. The products of the process, β-hydroxy-ketones and α,β-unsaturated ketones, are useful for the preparation of many commercially important products in the chemical process industries including solvents, drug intermediates, flavors and fragrances, other specialty chemical intermediates.
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- PROCESSES FOR THE PREPARATION OF HIGHER MOLECULAR WEIGHT SATURATED KETONES
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Continuous single-step processes for producing higher molecular weight ketones are disclosed that involve a liquid-phase crossed condensation of an aldehyde with a ketone in the presence of a hydrogenation catalyst and a small amount of a catalyst comprising a concentrated hydroxide or alkoxide of an alkali-metal (from Group 1 or Group IA of the Periodic Table of the Elements) or alkali-earth metal (from Group 2, or Group IIA of the Periodic Table of the Elements), wherein the amount of water provided to the reaction mixture, or reaction zone, is relatively low, with respect to the total initial weight of the reaction mixture. The reaction may be carried out in the absence of solubilizing agents or phase transfer agents. The product mixture is largely free of by-products resulting from further condensation reactions of the desired ketone product or intermediates, and free of the self-condensation products of the reactant aldehyde, that are afterward difficult to remove from the reaction mixture.
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Page/Page column 9-11
(2008/06/13)
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- Processes for the preparation of higher molecular weight ketones
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Processes for producing higher molecular weight ketones are disclosed that include the steps of feeding an aldol catalyst solution, a lower molecular weight aldehyde, and a lower molecular weight ketone, through a reactor provided with a solid hydrogenation catalyst and hydrogen gas; recovering a liquid reactor effluent containing the higher molecular weight ketone as a reaction product; and recycling a portion of the recovered liquid reactor effluent back through the reactor.
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- Synthesis of α,β-unsaturated ketone from α-iodo ketone using photoirradiation
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Irradiation of α-iodo ketone in hexane under a nitrogen atmosphere with a high-pressure mercury lamp (λ>300nm) at room temperature afforded the corresponding α,β-unsaturated ketones in good yield. This reaction affords a new, clean and convenient synthetic method for the α,β-unsaturated ketone.
- Ji, Shun-Jun,Takahashi, Eiji,Takahashi, T. Tomoyoshi,Horiuchi, C. Akira
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p. 9263 - 9266
(2007/10/03)
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