99-67-2Relevant academic research and scientific papers
A Selective and Functional Group-Tolerant Ruthenium-Catalyzed Olefin Metathesis/Transfer Hydrogenation Tandem Sequence Using Formic Acid as Hydrogen Source
Zieliński, Grzegorz K.,Majtczak, Jaros?awa,Gutowski, Maciej,Grela, Karol
, p. 2542 - 2553 (2018/03/09)
A ruthenium-catalyzed transfer hydrogenation of olefins utilizing formic acid as a hydrogen donor is described. The application of commercially available alkylidene ruthenium complexes opens access to attractive C(sp3)-C(sp3) bond formation in an olefin metathesis/transfer hydrogenation sequence under tandem catalysis conditions. High chemoselectivity of the developed methodology provides a remarkable synthetic tool for the reduction of various functionalized alkenes under mild reaction conditions. The developed methodology is applied for the formal synthesis of the drugs pentoxyverine and bencyclane.
A 2 - (2-allyl) pentene-4-acid methyl ester preparation method (by machine translation)
-
Paragraph 0016; 0019, (2017/03/14)
The invention relates to a machine intermediate 2 - (2-allyl) pentene-4-acid methyl ester preparation method, the preparation method is as follows: step 1) malonic acid ring (inferior) of potassium hydroxide in isopropyl acetate under alkaline conditions by PEG-400 catalytic and 3-polybromide propylene reaction produce compound 1 ; step 2) compound 1 under alkaline conditions in the sodium hydroxide of hydrolyzed to generate β-b acid compound 2 ; step 3) β-b acid compound 2 is heated and a single carboxyl the carboxyl group lives 3 ; step 4) single carboxyl compound 3 is obtained by reacting the methyl ester of the methyl esterification of compound 4 ; step 5) methyl ester compound 4 under alkaline conditions in and again LDA 3-polybromide propylene reaction produce the target compound 5. In the method for preparing the raw materials of the malonic acid ring a (sub) and isopropyl acetate 3-polybromide propylene, low cost, small synthetic process step, the operation is simple, convenient extraction and purification, the yield can reach 80% or more. (by machine translation)
In tandem or alone: A remarkably selective transfer hydrogenation of alkenes catalyzed by ruthenium olefin metathesis catalysts
Zieliski, Grzegorz Krzysztof,Samojlowicz, Cezary,Wdowik, Tomasz,Grela, Karol
supporting information, p. 2684 - 2688 (2015/04/14)
A system for transfer hydrogenation of alkenes, composed of a ruthenium metathesis catalyst and HCOOH, is presented. This operationally simple system can be formed directly after a metathesis reaction to effect hydrogenation of the metathesis product in a single-pot. These hydrogenation conditions are applicable to a wide range of alkenes and offer remarkable selectivity. This journal is
Oxidative rearrangement of malondialdehyde: Substrate scope and mechanistic insights
Yu, Xin,Liu, Zheng,Xia, Zilei,Shen, Zhigao,Pan, Xixian,Zhang, Hui,Xie, Weiqing
, p. 53397 - 53401 (2015/01/16)
A novel oxidative rearrangement of malondialdehyde was described. Under the effect of H2O2, malondialdehyde smoothly transferred to carboxylic acid with C-C bond cleavage in good to excellent yields. Mechanistic studies showed that this reaction proceeded via the formation of a 1,2-dioxolane intermediate, followed by concert C-C, O-O, C-H bond cleavage and a hydride shift.
Use of ethyl (benzothiazol-2-ylsulfonyl)acetate for malonic ester-type syntheses of carboxylic acids and esters
Hussein, Waleed M.,McGeary, Ross P.
, p. 1222 - 1227 (2014/10/16)
A new methodology for the synthesis of substituted carboxylic acids is described. Alkylation of either ethyl (benzothiazol-2-ylsulfonyl)acetate or ethyl 2-(benzothiazol-2-ylsulfonyl)propionate was achieved with alkyl halides and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) in dichloromethane solution. These products were then desulfinated and hydrolysed in one-pot under mild conditions to give substituted acetic acids in good-to-excellent yields.
Study on the total synthesis of velbanamine: Chemoselective dioxygenation of alkenes with PIFA via a stop-and-flow strategy
Liu, Huili,Zheng, Kuan,Lu, Xiang,Wang, Xiaoxia,Hong, Ran
supporting information, p. 983 - 990 (2013/07/19)
A "stop-and-flow" strategy was developed for the chemoselective dioxygenation of alkenes with a PIFA-initiated cyclization. This method is conceived for the desymmetrization of seco-diene, and a series of substituted 5-hydroxymethyl-γ-lactones were constructed after hydrolysis. This strategy also differentiates terminally substituted alkenes and constitutes a potentially novel synthetic approach for the efficient synthesis toward velbanamine.
Metal-free oxyaminations of alkenes using hydroxamic acids
Schmidt, Valerie A.,Alexanian, Erik J.
supporting information; experimental part, p. 11402 - 11405 (2011/09/16)
A radical-mediated approach to metal-free alkene oxyamination is described. This method capitalizes on the unique reactivity of the amidoxyl radical in alkene additions to furnish a general difunctionalization using simple diisopropyl azodicarboxylate (DIAD) as a radical trap. This protocol capitalizes on the intramolecular nature of the process, providing single regioisomers in all cases. Difunctionalizations of cyclic alkenes provide trans oxyamination products inaccessible using current methods with high levels of stereoselectivity, complementing cis-selective oxyamination processes.
Metal-free, aerobic dioxygenation of alkenes using hydroxamic acids
Schmidt, Valerie A.,Alexanian, Erik J.
supporting information; experimental part, p. 4491 - 4494 (2010/08/21)
(Chemical equation presented) One dioxygenation please, hold the metal: In the presence of either oxygen or air as the sole oxidant and external oxygen atom source, a variety of unsaturated hydroxamic acids afford cyclic hydroxamates that are readily converted into 1,2-diols, with the potential for high levels of reaction stereocontrol.
Insights into the formation of symmetrical trimers of dialkylated ketenes starting from acid chloride precursors
Saaidi, Pierre-Loic,Doridot, Gabriel,Jeanneau, Erwann,Hasserodt, Jens
, p. 1011 - 1018 (2008/03/17)
Application of known dialkyl ketene di- and trimerization to more complex precursors could readily open the route to highly functionalized symmetrical cyclobuta-1,3-diones and cyclohexa-1,3,5-triones. We report herein the results on three substrates containing either a C=C double bond or a protected glycol moiety as illustrative functionalized groups. The nature of the substituents is found to be crucial: while cyclopentenyl and more constrained dioxolanocyclopentenyl precursors efficiently dimerize, a diallylic derivative fails. At the millimolar scale, methoxide-catalyzed trimerization shows limited reproducibility, even for the reported substrate tetramethylcyclobuta-1,3-dione. However, systematic studies, including the use of microwaves, demonstrate that formation of symmetrical trimers is favored under solvent-free conditions and conventional heating, which allowed us to isolate and characterize trispiro[4.1.4.1.4.1]octadeca-2,9,15-triene-6,12,18-trione.
Reactions of 2-(perfluoroalkyl)ethane thiols with 1,6-heptadiene and 4-substituted 1,6-heptadienes: The synthesis of RFethanethio- cyclopentanoic and -dioic acids; and, "geminal-twin-tail" bis-(perfluoroalkylethanethio)alkanoic acids
Brace, Neal O.
, p. 7 - 15 (2007/10/03)
Kinetic analysis of the free radical addition of n-C6F 13I to 1,6-heptadiene gives a rate ratio of cyclization to addition (kd1/kc) of 0.568 at 70°C; thus, the rate of cyclization (kc) is twice that of iodine transfer (kd1). By contrast, for n-C6F13CH2CH2SH (kd1/kc) = 14.4 at 70°C, and radical transfer of H from the thiol is 14.4 times the faster than cyclization. Substitution at the center of 1,6-heptadiene has a profound effect on the linear/cyclic adduct ratio. For the addition of n-C3F7I (RFI:diene= 2:0) the adduct ratios dramatically decrease in the order: 1,6-heptadiene (1.17) > 4-carboxy-1,6-heptadiene (0.0613) > 4,4-bis-ethoxycarbonyl-1,6- heptadiene (F(CH 2)3]2CHCO2R, or [R F(CH2)3]2C(CO2R) 2 must be synthesized by other means. For the reaction of R FCH2CH2SH with the dienes (1:1), the respective adduct ratios are 11.3 (n-C6F13), 0.370 (n-C 8F17), and 0.0716 (n-C6F13). However, adding the 4-carboxy-1,6-heptadiene slowly to four mols of n-C 8F17CH2CH2SH yields 98% of the geminal bis-adduct [RFCH2CH2S(CH 2)3]2CHCO2H, which is a new, fluorophilic, geminal-twin-tail acid.
