1846-68-0Relevant articles and documents
Palladium-catalyzed oxidative borylation of conjugated enynones through carbene migratory insertion: synthesis of furyl-substituted alkenylboronates
Ping, Yifan,Chang, Taiwei,Wang, Kang,Huo, Jingfeng,Wang, Jianbo
supporting information, p. 59 - 62 (2019/01/03)
A palladium-catalyzed oxidative borylation reaction of conjugated enynones is developed. This reaction represents a new method for the synthesis of furyl-substituted alkenylboronates. The reaction works well with a series of conjugated enynones. Boryl migratory insertion of the palladium carbene intermediate is proposed as the key step in these transformations.
Chemoselective Biohydrogenation of Alkenes in the Presence of Alkynes for the Homologation of 2-Alkynals/3-Alkyn-2-ones into 4-Alkynals/Alkynols
Colombo, Danilo,Brenna, Elisabetta,Gatti, Francesco G.,Ghezzi, Maria Chiara,Monti, Daniela,Parmeggiani, Fabio,Tentori, Francesca
supporting information, p. 2638 - 2648 (2019/05/16)
The chemoselective hydrogenation of alkenes in the presence of alkynes is a very challenging transformation to achieve with traditional chemical methods. The development of an effective procedure to perform this transformation would enrich the tool-kit available to organic chemists for the development of useful synthetic routes, and the creation of novel structural motifs. The reduction of activated alkene bonds by ene-reductases (ERs) is completely chemoselective, because of the mechanism of the reaction. Thus, we investigated the use of ERs belonging to the Old Yellow Enzyme family for the reduction of α,β-unsaturated aldehydes with a conjugated C≡C triple bond at the γ position. This reaction was exploited as the key step for the development of an effective homologation route to convert aryl and alkyl substituted propynals and butynones into 4-alkynals and 4-alkynols, avoiding some troublesome or hazardous steps of known synthetic routes. (Figure presented.).
Catalyst-Free Annulation of 2-Pyridylacetates and Ynals with Molecular Oxygen: An Access to 3-Acylated Indolizines
Chen, Zhengwang,Liang, Pei,Ma, Xiaoyue,Luo, Haiqing,Xu, Guohai,Liu, Tanggao,Wen, Xiaowei,Zheng, Jing,Ye, Hui
supporting information, p. 1630 - 1639 (2019/01/26)
A catalyst and additive-free annulation of 2-pyridylacetates and ynals under molecular oxygen was the first developed, affording 3-acylated indolizines in good to excellent yields. Molecular oxygen was used as the source of the carbonyl oxygen atom in indolizines. This approach was compatible with a wide range of functional groups, and especially it has been successfully extended to unsaturated double bonds and triple bonds, which were difficult to prepare by previous methods in a single step.
Synthetic method for organic synthesis intermediate 2-octynaldehyde
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Paragraph 0012; 0013; 0016; 0017; 0018 - 0021, (2018/07/30)
The invention discloses a synthetic method for the organic synthesis intermediate 2-octynaldehyde. The synthetic method comprises the following steps: adding 2-octyne-1-propyl ether and an anhydrous 2-bromopropane solution into a reaction vessel, controlling a solution temperature and a stirring speed, and carrying out a reaction; and then adding cadmium selenide powder and an anhydrous ethylene glycol carbonate solution in batches, raising the temperature, continuing the reaction, lowering the temperature, carrying out standing, subjecting the solution to layering, separating an oil layer, washing the oil layer in an anhydrous 2,5-dimethylfuran solution a plurality of times, then washing the oil layer in an anhydrous dimethyl sulphoxide solution a plurality of times, carrying out recrystallization in an anhydrous diethylene glycol solution, and then carrying out dehydration with a dehydrating agent to obtain the finished 2-octynaldehyde.
[4+2] or [4+1] Annulation: Changing the Reaction Pathway of a Rhodium-Catalyzed Process by Tuning the Cp Ligand
Hong, Seung Youn,Jeong, Jisu,Chang, Sukbok
supporting information, p. 2408 - 2412 (2017/02/23)
A change in reaction pathway was achieved for the first time by tuning the cyclopentadienyl (Cp) ligand used for the rhodium-catalyzed cyclization of benzamides with conjugated enynones. Depending on the Cp ligand, the reaction pathway switched between [4+2] and [4+1] annulation. Electronic effects turned out to be crucial for the product distribution. The dichotomy was attributed to the alteration of the Lewis acidity of the resultant Cp-bound rhodium species.
Catalytic Enantioselective Synthesis of Amino Skipped Diynes
Paioti, Paulo H. S.,Abboud, Khalil A.,Aponick, Aaron
supporting information, p. 2150 - 2153 (2016/03/05)
The Cu-catalyzed synthesis of nonracemic 3-amino skipped diynes via an enantiodetermining C-C bond formation is described using StackPhos as ligand. Despite challenging issues of reactivity and stereoselectivity inherent to these chiral skipped diynes, the reaction tolerates an extremely broad substrate scope with respect to all components and provides the title compounds in excellent enantiomeric excess. The alkyne moieties are demonstrated here to be useful synthetic handles, and 3-amino skipped diynes are convenient building blocks for enantioselective synthesis.
Palladium-Catalyzed Oxidative Cross-Coupling of Conjugated Enynones with Organoboronic Acids
Xia, Ying,Ge, Rui,Chen, Li,Liu, Zhen,Xiao, Qing,Zhang, Yan,Wang, Jianbo
, p. 7856 - 7864 (2015/09/01)
A palladium-catalyzed oxidative cross-coupling reaction of conjugated enynones with organoboronic acids is developed. This reaction provides an efficient methodology for the synthesis of functionalized furan derivatives, including 2-alkenylfurans and furan-substituted 1,3-dienes. Palladium-carbene migratory insertion is proposed as the key step in these transformations. Notably, the β-hydride elimination process occurs in a stereoselective manner, resulting in the formation of double bonds with high (E)-selectivity.
Pd-catalyzed cross-coupling of terminal alkynes with ene-yne-ketones: Access to conjugated enynes via metal carbene migratory insertion
Xia, Ying,Liu, Zhen,Ge, Rui,Xiao, Qing,Zhang, Yan,Wang, Jianbo
supporting information, p. 11233 - 11235 (2015/07/07)
A novel strategy for alkyne-alkyne cross-coupling has been developed under the palladium catalysis. In this reaction, ene-yne-ketones are employed as carbene precursors, which couple with terminal alkynes through the metal carbene migratory insertion process. Furan-substituted enynes are obtained in good yields and in a stereoselective manner.
Copper(II)-catalyzed silylation of activated alkynes in water: Diastereodivergent access to E- or Z-β-silyl-α,β-unsaturated carbonyl and carboxyl compounds
Calderone, Joseph A.,Santos, Webster L.
supporting information, p. 4154 - 4158 (2014/05/06)
Copper(II)-catalyzed silylation of substituted alkynylcarbonyl compounds was investigated. Through the activation of Me2PhSiBpin in water at room temperature and open atmosphere, vinylsilanes conjugated to carbonyl groups are synthesized in high yield. A surprising diastereodivergent access to olefin geometry was discovered using a silyl conjugate addition strategy: aldehydes and ketones were Z selective while esters and amides were exclusively transformed into the E products. Dial a diastereomer: The title reaction proceeds through the activation of Me2PhSiBpin in water at room temperature and open atmosphere to produce high yields of vinylsilanes conjugated to carbonyl groups. A surprising diastereodivergent access to olefin geometry was discovered using this silyl conjugate addition strategy: aldehydes were Z selective while esters and amides exclusively delivered the E-configured products.
Copper-Catalyzed Propargylic Substitution of Dichloro Substrates: Enantioselective Synthesis of Trisubstituted Allenes and Formation of Propargylic Quaternary Stereogenic Centers
Li, Hailing,Grassi, David,Guénée, Laure,Bürgi, Thomas,Alexakis, Alexandre
supporting information, p. 16694 - 16706 (2016/02/12)
An easy and versatile Cu-catalyzed propargylic substitution process is presented. Using easily prepared prochiral dichloro substrates, readily available Grignard reagents together with catalytic amount of copper salt and chiral ligand, we accessed a range of synthetically interesting trisubstituted chloroallenes. Substrate scope and nucleophile scope are broad, providing generally high enantioselectivity for the desired 1,3-substitution products. The enantioenriched chloroallenes could be further transformed into the corresponding trisubstituted allenes or terminal alkynes bearing all-carbon quaternary stereogenic centers, through the copper-catalyzed enantiospecific 1,1/1,3-substitutions. The two successive copper-catalyzed reactions could be eventually combined into a one-pot procedure and different desired allenes or alkynes were obtained respectively with high enantiomeric excesses.
