14804-59-2Relevant academic research and scientific papers
Conceptual approach to the synthesis of symmetrical 1,3-diynes from β-bromo vinyl carboxylic acids
Singha, Raju
, (2020)
Abstract: A conceptual route has been developed for the synthesis of 1,3-diyne from β-bromo vinyl carboxylic acids. The reaction of the β-bromo vinyl carboxylic acid with palladium catalyst is conceptually similar to the decomposition of 2-diazoniumbenzoic acid to benzyne. In the presence of palladium catalyst, the β-bromo vinyl carboxylic acid undergoes a fragmentation to generate terminal alkyne. The terminal alkyne undergoes dimerisation in the presence of palladium catalysts to produce the product 1,3-diyne. Graphic abstract: A conceptual route has been developed for the synthesis of 1,3-diyne from β-bromo vinyl carboxylic acids. To the best of our knowledge, we are the first ones reporting the synthesis of 1,3-diyne in a catalytic way without the requirement of any prefunctionalized alkyne unit(s).[Figure not available: see fulltext.]
Copper and Rhodium Relay Catalysis for Selective Access to cis-2,3-Dihydroazepines
Du, Luan,Li, Baosheng,Li, Shanshan,Li, Yingzi,Li, You,Luo, Han,Tang, Zongyuan,Xin, Xiaolan
supporting information, p. 6450 - 6454 (2021/08/30)
A new catalytic protocol to access synthetically challenging cis-2,3-dihydroazepines is reported. The reaction starts with readily available dienals, alkynes, and sulfonyl azides as the substrates and employs copper and rhodium as relay catalysts. Key steps include a copper-catalyzed reaction between an alkyne and a sulfonyl azide to form a triazole intermediate. The subsequent activation of this triazole intermediate by a rhodium catalyst, followed by a reaction with the dienal substrate, eventually leads to the dihydroazepine product. The regio- and stereochemistries of the products are believed to be controlled through a stereospecific conrotatory 8π-electrocyclization process against a possible competing 6π-electrocyclization process.
A Strategy To Obtain o-Naphthoquinone Methides: Ag(I)-Catalyzed Cyclization of Enynones for the Synthesis of Benzo[ h]chromanes and Naphthopyryliums
Wu, Feng,Zhu, Shifa
supporting information, (2019/03/08)
A new strategy to obtain o-NQM intermediates through a ring-formation strategy by Ag(I)-catalyzed cyclization of 2-alkenylphenyl alkynyl ketones and its [4 + 2] annulations with styrenes has been developed. This reaction features high efficiency, mild reaction conditions, as well as flexible substitutions and atom economy. The obtained benzo[h]chromane products were further oxidized to naphthopyryliums, which displayed tunable photophysical properties.
Exploiting Hydrazones to Improve the Efficiency of 6π-Electrocyclization Reactions of 1-Azatrienes
Ball-Jones, Matthew P.,Tyler, Jasper,Mora-Radó, Helena,Czechtizky, Werngard,Méndez, María,Harrity, Joseph P. A.
supporting information, p. 6821 - 6824 (2019/09/07)
The greater geometric lability of hydrazones compared to that of oxime ethers is used as a basis to overcome the reluctance of Z-oxime ether azatrienes to undergo electrocyclization toward the synthesis of borylated (heteroaromatic) pyridines and ring-fused analogues. Such hydrazones now allow access to previously inaccessible tri- and tetrasubstituted 3-borylpyridines in high yields.
Atroposelective Arene Formation by Carbene-Catalyzed Formal [4+2] Cycloaddition
Xu, Ke,Li, Wenchang,Zhu, Shaoheng,Zhu, Tingshun
supporting information, p. 17625 - 17630 (2019/11/29)
Atroposelective arene formation is an efficient method to build axially chiral molecules with multi-substituted arenes. Reported here is an organocatalyzed atroposelective arene formation reaction by an N-heterocyclic carbene (NHC) catalyzed formal [4+2] cycloaddition of conjugated dienals and α-aryl ketones. This study expands the synthetic potential of NHC organocatalysis and provides a competitive pathway for the synthesis of axially chiral ligands, catalysts, and other functional molecules.
Biocatalysis with the milk protein β-lactoglobulin: Promoting retroaldol cleavage of α,β-unsaturated aldehydes
Gowda, Vishruth,Foley, Brendan,Du, Jasmine,Esteb, Megan,Watanabe, Coran M. H.
, p. 2210 - 2213 (2018/04/05)
Enzymes with a hydrophobic binding site and an active site lysine have been suggested to be promiscuous in their catalytic activity. β-Lactoglobulin (BLG), the principle whey protein found in milk, possesses a central calyx that binds non-polar molecules. Here, we report that BLG can catalyze the retro-aldol cleavage of α,β-unsaturated aldehydes making it a naturally occurring protein capable of catalyzing retro-aldol reactions on hydrophobic substrates. Retroaldolase activity was seen to be most effective on substrates with phenyl or naphthyl side-chains. Use of a brominated substrate analogue inhibitor increases the product yield by a factor of three. BLG's catalytic activity and its ready availability make it a prime candidate for the development of commercial biocatalysts.
Gold-Catalyzed Ring Expansion of Enyne-Lactone: Generation and Transformation of 2-Oxoninonium
Luo, Kui,Cao, Tongxiang,Jiang, Huanfeng,Chen, Lianfen,Zhu, Shifa
supporting information, p. 5856 - 5859 (2017/11/10)
An efficient gold-catalyzed ring-expansion reaction of enyne-lactones to form 2-oxoninonium intermediates is reported. The 2-oxoninonium generated in this work could undergo further 6π electrocyclization and aromatization reaction to produce different aromatic compounds.
Stitching Oxindoles and Ynones in a Domino Process: Access to Spirooxindoles and Application to a Short Synthesis of Spindomycin B
Samineni, Ramesh,Madapa, Jaipal,Pabbaraja, Srihari,Mehta, Goverdhan
supporting information, p. 6152 - 6155 (2017/11/24)
A general, transition-metal-free, one-pot, domino Michael-SNAr or AdNE substitution protocol was devised for spiroannulation of oxindoles with ortho-bromoaryl ynones, β-bromoalkenyl ynones, and β-bromoalkenyl enones in a convenient a
Intramolecular cascade rearrangements of enynamine derived ketenimines: Access to acyclic and cyclic amidines
Chauhan, Dinesh Pratapsinh,Varma, Sreejith J.,Gudem, Mahesh,Panigrahi, Nihar,Singh, Khushboo,Hazra, Anirban,Talukdar, Pinaki
supporting information, p. 4822 - 4830 (2017/07/10)
Copper-catalyzed reaction of enynamines with sulfonylazides provides acyclic and cyclic amidines. Nucleophilic addition of the tethered amino group on the in situ generated ketenimine forms a six-membered cyclic zwitterionic intermediate which facilitates
N-heterocyclic carbene-catalyzed δ-Carbon LUMO activation of unsaturated aldehydes
Zhu, Tingshun,Mou, Chengli,Li, Baosheng,Smetankova, Marie,Song, Bao-An,Chi, Yonggui Robin
supporting information, p. 5658 - 5661 (2015/05/20)
An N-heterocyclic carbene (NHC) catalyzed domino reaction triggered by a δ-LUMO activation of α,β-γ,δ-diunsaturated enal has been developed for the formal [4 + 2] construction of multisubstituted arenes and 3-ylidenephthalide. These two products, formed i
