2892-18-4Relevant articles and documents
Enantioselective Construction of Quaternary Stereogenic Centers by the Addition of an Acyl Anion Equivalent to 1,3-Dienes
Adamson, Nathan J.,Malcolmson, Steven J.,Nguyen, Andrew L.,Park, Sangjune,Zhou, Pengfei
supporting information, (2020/03/04)
We report the enantioselective formation of quaternary stereogenic centers by the intermolecular addition of malononitrile, an acyl anion equivalent, and related pronucleophiles to several 1,3-disubstituted acyclic 1,3-dienes in the presence of a Pd-PHOX catalyst. Products are obtained in up to 88% yield and 99:1 er and in most cases are formed as a single regioisomer. The products' malononitrile unit undergoes oxidative functionalization to afford β,γ-unsaturated carbonyls bearing internal olefins and α-quaternary stereogenic centers.
Method for preparing alpha and beta-unsaturated ketone
-
Paragraph 0012; 0013; 0034; 0035; 0036; 0040; 0041, (2016/10/31)
The invention provides a method for preparing alpha and beta-unsaturated ketone. The method includes that L-proline is used as a catalyst, secondary amine is used as a cocatalyst, and the alpha and beta-unsaturated ketone can be directly synthesized in alcohol or ketone solution by means of aldol condensation under neutral conditions at one step. Compared with the traditional method, the method has the advantages that raw materials are easily available, the method is low in cost and is environmental friendly, reaction conditions are mild, solvents are clean and environmental friendly, equipment can be protected against corrosion under the neutral conditions, the catalyst is high in acid resistance, and the method is applicable to industrial production.
Kinetic Resolution of Racemic Allylic Alcohols by Catalytic Asymmetric Substitution of the OH Group with Monosubstituted Hydrazines
Yan, Liang,Xu, Jing-Kun,Huang, Chao-Fan,He, Zeng-Yang,Xu, Ya-Nan,Tian, Shi-Kai
supporting information, p. 13041 - 13045 (2016/09/09)
A new strategy has been established for the kinetic resolution of racemic allylic alcohols through a palladium/sulfonyl-hydrazide-catalyzed asymmetric OH-substitution under mild conditions. In the presence of 1 mol % [Pd(allyl)Cl]2, 4 mol % (S)-SegPhos, and 10 mol % 2,5-dichlorobenzenesulfonyl hydrazide, a range of racemic allylic alcohols were smoothly resolved with selectivity factors of more than 400 through an asymmetric allylic alkylation of monosubstituted hydrazines under air at room temperature. Importantly, this kinetic resolution process provided various allylic alcohols and allylic hydrazine derivatives with high enantiopurity.
Potent and Selective Inhibitors of Trypanosoma cruzi Triosephosphate Isomerase with Concomitant Inhibition of Cruzipain: Inhibition of Parasite Growth through Multitarget Activity
Aguilera, Elena,Varela, Javier,Birriel, Estefanía,Serna, Elva,Torres, Susana,Yaluff, Gloria,de Bilbao, Ninfa Vera,Aguirre-López, Beatriz,Cabrera, Nallely,Díaz Mazariegos, Selma,de Gómez-Puyou, Marieta Tuena,Gómez-Puyou, Armando,Pérez-Montfort, Ruy,Minini, Lucia,Merlino, Alicia,Cerecetto, Hugo,González, Mercedes,Alvarez, Guzmán
supporting information, p. 1328 - 1338 (2016/07/20)
Triosephosphate isomerase (TIM) is an essential Trypanosoma cruzi enzyme and one of the few validated drug targets for Chagas disease. The known inhibitors of this enzyme behave poorly or have low activity in the parasite. In this work, we used symmetrical diarylideneketones derived from structures with trypanosomicidal activity. We obtained an enzymatic inhibitor with an IC50value of 86 nm without inhibition effects on the mammalian enzyme. These molecules also affected cruzipain, another essential proteolytic enzyme of the parasite. This dual activity is important to avoid resistance problems. The compounds were studied in vitro against the epimastigote form of the parasite, and nonspecific toxicity to mammalian cells was also evaluated. As a proof of concept, three of the best derivatives were also assayed in vivo. Some of these derivatives showed higher in vitro trypanosomicidal activity than the reference drugs and were effective in protecting infected mice. In addition, these molecules could be obtained by a simple and economic green synthetic route, which is an important feature in the research and development of future drugs for neglected diseases.
Organoselenium-catalyzed baeyer-villiger oxidation of α,β-unsaturated ketones by hydrogen peroxide to access vinyl esters
Zhang, Xu,Ye, Jianqing,Yu, Lei,Shi, Xinkang,Zhang, Ming,Xu, Qing,Lautens, Mark
supporting information, p. 955 - 960 (2015/03/30)
By carefully screening the organoselenium pre-catalysts and optimizing the reaction conditions, simple dibenzyl diselenide was found to be the best pre-catalyst for Baeyer-Villiger oxidation of (E)-α,β-unsaturated ketones with the green oxidant hydrogen peroxide at room temperature. The organoselenium catalyst used in this reaction could be recycled and reused several times. This new method was suitable not only for methyl unsaturated ketones, but also for alkyl and aryl unsaturated ketones. Therefore, it provided a direct, mild, practical, highly functional group-tolerant process for the chemoselective preparation of the versatile (E)-vinyl esters from the readily available (E)-α,β-unsaturated ketones. A possible mechanism was also proposed to rationalize the activity of the organoselenium catalyst in the presence of hydrogen peroxide in this Baeyer-Villiger oxidation reaction.
Oxygen as single oxidant for two steps: Base-free one-pot Pd(ii)-catalyzed alcohol oxidation & arylation to halogen-intact β-aryl α,β-enones
Vellakkaran, Mari,Andappan, Murugaiah M. S.,Nagaiah, Kommu
, p. 45490 - 45494 (2014/12/10)
Using oxygen as the sole oxidant for two steps, we developed a new method to synthesize β-aryl α,β-enones by fine-tuning the Pd(ii)-catalyzed oxidation of allyl alcohol to subsequent arylation with arylboronic acids, arylboronic ester and aryltrifluoroborate salt. This one-pot green method does not require copper salt, base, and intermediate isolation. Halogen-bearing chalcones, dibenzylideneacetones and arylalkyl enones were synthesized in good yields. This journal is
Reaction behavior of cyclopropylmethyl cations derived 1-phenylselenocyclopropylmethanols with acids
Honda, Mitsunori,Nishizawa, Toshiaki,Nishii, Yuko,Fujinami, Shuhei,Segi, Masahito
experimental part, p. 9403 - 9411 (2009/12/28)
The 1-phenylselenocyclopropylmethyl cations are generated by the reaction of the corresponding cyclopropylmethanols 1 with TsOH. The reaction in methanol proceeds to afford the homoallylic ethers 2, ring-enlargement products 3, 4, and ring opening product
Study of the reaction of 1,1-bis(trimethylsilyl)-2-phenylethylene with some acyl chlorides in the presence of AlCl3
Safa, Kazem D.,Samani, Soleiman Paymard,Tofangdarzadeh, Shahin,Hassanpour, Akbar
, p. 2004 - 2008 (2008/09/19)
1,1-Bis(trimethylsilyl)-2-phenylethylene (1), which has been synthesized from the Peterson reaction between (Me3Si)3CLi and benzaldehyde, reacts with various acyl chlorides (RCOCl, R = Me, Et, iso-Pr, n-Bu, iso-Bu, iso-C5H11, PhCH2, PhCH2CH2) in the presence of AlCl3 to give α-silyl-α,β-unsaturated enones 3a-3h with high E stereoselectivity along with trans-α,β-unsaturated ketones 4a-4h. The enones 3 can be partially converted into the ketones 4 with an excess of AlCl3. Reaction of 1 with RCOCl, (R = Ph, CH3CH=CH) afforded only the ketones 4. Yields were dependent on time and the amounts of AlCl3 used.
Acid-catalyzed reaction behavior of 1-phenylselenocyclopropylmethanols
Honda, Mitsunori,Nishizawa, Toshiaki,Nishii, Yuko,Segi, Masahito
scheme or table, p. 946 - 947 (2009/04/05)
The reaction of 1-phenylselenocyclopropylmethanols with TsOH in methanol proceeded smoothly to afford the homoallylic ethers, ring-enlargement products, and ring-opening products depending upon the kind of substituent on the cyclopropane ring or α-carbon.
Preparation of aryl-substituted E-homoallylic bromides from cyclopropylcarbinol and PBr3
Roy, Sanchita,Guha, Sharmistha,Kumar Dutta, Samit,Bhar, Sanjay
, p. 1919 - 1922 (2007/10/03)
An expeditious synthesis of aryl substituted E-homoallylic bromides has been accomplished by the cleavage of cyclopropylcarbinols with phosphorus tribromide. Copyright Taylor & Francis Group, LLC.