16519-25-8Relevant academic research and scientific papers
Synthesis of Enantioenriched 3,4-Disubstituted Chromans through Lewis Base Catalyzed Carbosulfenylation
Denmark, Scott E.,Laverny, Aragorn,Menard, Travis
, p. 14290 - 14310 (2021/11/12)
A method for the catalytic, enantioselective, carbosulfenylation of alkenes to construct 3,4-disubstituted chromans is described. Alkene activation proceeds through the intermediacy of enantioenriched, configurationally stable thiiranium ions generated from catalytic, Lewis base activation of an electrophilic sulfenylating agent. The transformation affords difficult-to-generate, enantioenriched, 3,4-disubstituted chromans in moderate to high yields and excellent enantioselectivities. A variety of substituents are compatible including electronically diverse functional groups as well as several functional handles such as aryl halides, esters, anilines, and phenols. The resulting thioether moiety is amenable to a number of functional group manipulations and transformations. Notably, the pendant sulfide was successfully cleaved to furnish a free thiol which readily provides access to most sulfur-containing functional groups which are present in natural products and pharmaceuticals.
Enantio- And regioselective asymmetric allylic substitution using a chiral aminophosphinite ruthenium complex: an experimental and theoretical investigation
Das, Dhiraj,Jena, Rajesh K.
, p. 39319 - 39327 (2021/12/24)
The design and synthesis of a new chiral aminophosphinite-ligated ruthenium complex is described. The ruthenium complex, [Ru(AMP)2(CH3CN)2][BPh4]2{AMP = (S)-tert-butyl 1-(diphenylphosphinooxy)-3-methylbutan-2-ylcarbamate}, has been found to catalyze nucleophilic addition of phenol and carboxylic acid to allyl chloride in a highly regioselective fashion with enantiomeric excess ranging from 12 to 90.
Selective Synthesis of Z-Cinnamyl Ethers and Cinnamyl Alcohols through Visible Light-Promoted Photocatalytic E to Z Isomerization
Li, Hengchao,Chen, Hang,Zhou, Yang,Huang, Jin,Yi, Jundan,Zhao, Hongcai,Wang, Wei,Jing, Linhai
supporting information, p. 555 - 559 (2020/02/05)
A photocatalytic E to Z isomerization of alkenes using an iridium photosensitizer under mild reaction conditions is disclosed. This method provides scalable and efficient access to Z-cinnamyl ether and allylic alcohol derivatives in high yields with excellent stereoselectivity. Importantly, this method also provides a powerful strategy for the selective synthesis of Z-magnolol and honokiol derivatives possessing potential biological activity.
Vinyl Sulfonium Salts as the Radical Acceptor for Metal-Free Decarboxylative Alkenylation
Zhang, Yu-Lan,Yang, Lei,Wu, Jie,Zhu, Chunyin,Wang, Peng
supporting information, p. 7768 - 7772 (2020/10/09)
Vinyl sulfonium salts typically act as an electrophilic Michael acceptor, thus initiating many tandem cyclization reactions. Herein, we disclosed the novel reactivity of vinyl sulfonium salts as a radical acceptor. Using redox-active ester as an alkyl rad
Covalent Organic Framework as a Heterogeneous Ligand for the Regioselective Oxidative Heck Reaction
Han, Jiyao,Sun, Xiaowei,Wang, Xiao,Wang, Qiong,Hou, Shenghuai,Song, Xin,Wei, Yingqin,Wang, Rongyu,Ji, Wenhua
supporting information, p. 1480 - 1484 (2020/03/13)
A simple imine-based covalent organic framework (COF) as heterogeneous ligand for PdII-promoted Heck reaction is reported. Good regioselectivity for a wide range of electronically unbiased olefins is obtained (linear/branched >100:1 in most cases). Related tests and density functional theory calculations are used to explore the reason underlying the high selectivity. This research opens a route for COF as an intriguing platform to control regioselectivity catalysis.
Cross-coupling reaction of allylic ethers with aryl Grignard reagents catalyzed by a nickel pincer complex
Hashimoto, Toru,Funatsu, Kei,Ohtani, Atsufumi,Asano, Erika,Yamaguchi, Yoshitaka
, (2019/07/10)
A cross-coupling reaction of allylic aryl ethers with arylmagnesium reagents was investigated using β-aminoketonato- and β-diketiminato-based pincer-type nickel(II) complexes as catalysts. An β-aminoketonato nickel(II) complex bearing a diphenylphosphino group as a third donor effectively catalyzed the reaction to afford the target cross-coupled products, allylbenzene derivatives, in high yield. The regioselective reaction of a variety of substituted cinnamyl ethers proceeded to give the corresponding linear products. In contrast, α- and γ-alkyl substituted allylic ethers afforded a mixture of the linear and branched products. These results indicated that the coupling reaction proceeded via a π-allyl nickel intermediate.
Base-Mediated O-Arylation of Alcohols and Phenols by Triarylsulfonium Triflates
Ming, Xiao-Xia,Tian, Ze-Yu,Zhang, Cheng-Pan
supporting information, p. 3370 - 3379 (2019/11/03)
A mild and efficient protocol for O-arylation of alcohols and phenols (ROH) by triarylsulfonium triflates was developed under transition-metal-free conditions. Various alcohols, including primary, secondary and tertiary, and phenols bearing either electron-donating or electron-withdrawing groups on the aryl rings were smoothly converted to form the corresponding aromatic ethers in moderate to excellent yields. The reactions were conducted at 50 or 80 °C for 24 h in the presence of a certain base and showed good functional group tolerance. The base-mediated arylation with asymmetric triarylsulfonium salts could selectively transfer the aryl groups of sulfoniums to ROH, depending on their inherent electronic nature. The mechanistic studies revealed that the reaction might proceed through the nucleophilic attack of the in situ formed alkoxy or phenoxy anions at the aromatic carbon atoms of the C?S bonds of triarylsulfonium cations to furnish the target products.
Constructing Mononuclear Palladium Catalysts by Precoordination/Solvothermal Polymerization: Recyclable Catalyst for Regioselective Oxidative Heck Reactions
Li, Wen-Hao,Li, Cun-Yao,Xiong, Huan-Yan,Liu, Yang,Huang, Wen-Yong,Ji, Guang-Jun,Jiang, Zheng,Tang, Hai-Tao,Pan, Ying-Ming,Ding, Yun-Jie
supporting information, p. 2448 - 2453 (2019/02/03)
Heterogeneous, metal, single-site catalysts often exhibit higher catalytic performance than other catalysts because of their maximized atom efficiency of 100 %. Reported herein is a precoordination/solvothermal polymerization strategy to fabricate a stabl
Halogen Bond Catalyzed Bromocarbocyclization
Chan, Yuk-Cheung,Yeung, Ying-Yeung
, p. 3483 - 3487 (2018/02/28)
A halogen bond catalyzed bromo-carbocyclization of N-cinnamyl sulfonamides and O-cinnamyl phenyl ethers has been developed. N-methyl 4-iodopyridinium triflate is used as the halogen-bonding organocatalyst and the reaction is highly chemoselective. This report represents the first proof-of-concept for halogen-bonding organocatalyst-promoted electrophilic halogenation. Mechanistic study suggests the autocatalytic nature of this reaction.
Pd-catalyzed substitution of the oh group of nonderivatized allylic alcohols by phenols
Rukkijakan, Thanya,Akkarasamiyo, Sunisa,Sawadjoon, Supaporn,Samec, Joseph S. M.
, p. 4099 - 4104 (2018/04/14)
Nonactivated phenols have been employed as nucleophiles in the allylation of nonderivatized allylic alcohols to generate allylated phenolic ethers with water as the only byproduct. A Pd[BiPhePhos] catalyst was found to be reactive to give the O-allylated phenols in good to excellent yields in the presence of molecular sieves. The reactions are chemoselective in which the kinetically favored O-allylated products are formed exclusively over the thermodynamically favored C-allylated products.
