6342-63-8Relevant academic research and scientific papers
α-Oxocarboxylic Acids as Three-Carbon Insertion Units for Palladium-Catalyzed Decarboxylative Cascade Synthesis of Diverse Fused Heteropolycycles
Zhou, Liwei,Qiao, Shujia,Zhou, Fengru,Xuchen, Xinyu,Deng, Guobo,Yang, Yuan,Liang, Yun
supporting information, p. 2878 - 2883 (2021/05/05)
A novel palladium-catalyzed decarboxylative cascade cyclization for the assembly of diverse fused heteropolycycles by employing α-oxocarboxylic acids as three-carbon insertion units is reported. This protocol enables the synthesis of isoquinolinedione- and indolo[2,1-a]isoquinolinone-fused benzocycloheptanones in moderate to good yields by the use of different aryl iodides, including alkene-tethered 2-iodobenzamides and 2-(2-iodophenyl)-1H-indoles. Notably, the approach achieves simultaneous construction of both six- and seven-membered rings via sequential intramolecular carbopalladation, C-H activation, and decarboxylation.
Atmosphere-Controlled Palladium-Catalyzed Divergent Decarboxylative Cyclization of 2-Iodobiphenyls and α-Oxocarboxylic Acids
Zhou, Liwei,Sun, Mingjie,Zhou, Fengru,Deng, Guobo,Yang, Yuan,Liang, Yun
supporting information, p. 7150 - 7155 (2021/09/18)
A novel palladium-catalyzed divergent decarboxylative cyclization of 2-iodobiphenyls and α-oxocarboxylic acids utilizing the atmosphere as a controlled switch is reported. Under the protection of a nitrogen atmosphere, tribenzotropones are synthesized by a [4 + 3] decarboxylative cyclization. Employing a palladium/O2 system enables a [4 + 2] decarboxylative cyclization to assemble triphenylenes. Notably, preliminary mechanistic studies indicate that the formation of triphenylenes involves a double decarboxylation.
Divergent Access to Benzocycles through Copper-Catalyzed Borylative Cyclizations
Yoon, Wan Seok,Han, Jung Tae,Yun, Jaesook
supporting information, p. 4953 - 4959 (2021/09/14)
A copper-catalyzed chemodivergent approach to five- and six-membered benzocycles from dienyl arenes tethered with a ketone has been developed. Through proper choice of coordinating ligands and catalytic conditions, copper-catalyzed borylative cyclization of a single dienyl arene can be diverted to two different pathways, leading to indanols and dihydronaphthalenols with high stereoselectivity. The chiral bidentate bisphosphine ligand (S,S)-Ph-BPE was optimal for asymmetric copper-allyl addition to a tethered ketone via a boat-like transition state, whereas NHC ligands led to boro-allyl addition producing indanols with high diastereoselectivity. (Figure presented.).
Enantiotropic Transformation of Carbethoxyhydrazones of Acetophenones
Bessonov, V. V.,Nepochatyi, G. D.,Petrov, M. L.,Pevzner, L. M.,Popova, E. A.,Stepanova, O. V.
, p. 311 - 313 (2020/04/15)
Abstract: Hydrazinecarboxylates have been synthesized by reacting substituted acetophenones with carbethoxyhydrazine. One of product is formed as a mixture of E- and Z-isomers. In the process of measuring the melting point of the resulting hydrazinecarbox
6,7-Benzotropolone Syntheses Based on Ring-Closing Metatheses and Four-Electron Oxidations
Brückner, Reinhard,Fernandes, Manuel A.,Gemander, Manuel,Green, Ivan R.,Kreibich, Michael,Peter, David,Yadav, Dharmendra B.,de Koning, Charles B.,van Otterlo, Willem A. L.
, (2020/05/18)
Four homoallyl ortho-vinylaryl ketones (10a-d) – 1,8-dienes of sorts – were prepared by several approaches. In the presence of 1–2 mol-% Grubbs-II catalyst, they ring-closed to give 6,7-dihydrobenzocyclohepten-5-ones (11a-d) in 90–96 % yield. With SeO2 the parent compound (11a) delivered benzocyclohepten-5-one (13a) and/or selenium-containing compounds (18–22) but no more than traces of 6,7-benzotropolone (5a). However, 5a was accessible from compound 11a via the sodium enolate and allowing it to react with a stream of oxygen (43 % yield). The sodium enolates of the substituted 6,7-dihydrobenzocyclohepten-5-ones 11b–d and oxygen underwent analogous 4-electron oxidations. This furnished the substituted 6,7-benzotropolones 11b-d. In contrast, the corresponding lithium enolates were inert towards oxygen. The 6,7-dihydrobenzocyclohepten-5-one 11d was also accessed differently, namely by a Grubbs-II catalyst-mediated RCM/C=C migration tandem reaction of the allyl ortho-allylaryl ketone 73 – another 1,8-diene of sorts (90 % yield).
Asymmetric Synthesis and Application of Chiral Spirosilabiindanes
Chang, Xin,Chen, Hong-Chao,Li, Chuan-Ying,Ma, Pei-Long,Wang, Peng
supporting information, p. 8937 - 8940 (2020/04/30)
Reported here is the development of a class of chiral spirosilabiindane scaffolds by Rh-catalyzed asymmetric double hydrosilation, for the first time. Enantiopure SPSiOL (spirosilabiindane diol), a new type of chiral building block for the preparation of various chiral ligands and catalysts, was readily prepared on greater than 10 gram scale using this protocol. The potential of this new spirosilabiindane scaffold in asymmetric catalysis was preliminarily demonstrated by development of the corresponding monodentate phosphoramidite ligands (SPSiPhos), which were used in both a Rh-catalyzed hydrogenation and a Pd-catalyzed intramolecular carboamination.
Mechanistic study on iodine-catalyzed aromatic bromination of aryl ethers by N-Bromosuccinimide
Pramanick, Pranab Kumar,Hou, Zhen-Lin,Yao, Bo
, p. 7105 - 7114 (2017/11/27)
Although iodine-catalyzed reaction has rapid advances in recent years, examples on iodine-catalyzed bromination are rare and the mechanism of these reactions remains unclear. Herein, we reported an I2-catalyzed aromatic bromination of aryl ethers by NBS and presented the details of the mechanistic study including kinetic study and the study of kinetic isotope effects. The study revealed that the reaction was actually catalyzed by IBr formed in the induction period, and the rate-determining step was the HBr-elimination of the Wheland intermediate assisted by IBr.
One-Pot Asymmetric Synthesis of Alkylidene 1-Alkylindan-1-ols Using Br?nsted Acid and Palladium Catalysis
Faggyas, Réka J.,Calder, Ewen D. D.,Wilson, Claire,Sutherland, Andrew
, p. 11585 - 11593 (2017/11/10)
A one-pot catalytic enantioselective allylboration/Mizoroki-Heck reaction of 2-bromoaryl ketones has been developed for the asymmetric synthesis of 3-methyleneindanes bearing a tertiary alcohol center. Br?nsted acid-catalyzed allylboration with a chiral BINOL derivative was followed by a palladium-catalyzed Mizoroki-Heck cyclization, resulting in selective formation of the exo-alkene. This novel protocol provides a concise and scalable approach to 1-alkyl-3-methyleneindan-1-ols in high enantiomeric ratios (up to 96:4 er). The potential of these compounds as chiral building blocks was demonstrated with efficient transformation to optically active diol and amino alcohol scaffolds.
Preparation of isoindolinones via a palladium-catalyzed diamination
Li, Yu,Kou, Xuezhen,Ye, Chenghao,Zhang, Xinghua,Yang, Guoqiang,Zhang, Wanbin
supporting information, p. 285 - 288 (2017/01/03)
A Pd(II)-catalyzed cyclization using oxidative olefin diamination was developed for the preparation of isoindolinones from ortho-olefinic N-methoxybenzamides. Using the optimized reaction conditions, the desired products were obtained in up to 90% yield using NFSI as the oxidant. This reaction provides an efficient and direct access to isoindolinones with amine functionality, an important drug skeleton.
Enantioselective Bromo-oxycyclization of Silanol
Xia, Zilei,Hu, Jiadong,Shen, Zhigao,Wan, Xiaolong,Yao, Qizheng,Lai, Yisheng,Gao, Jin-Ming,Xie, Weiqing
supporting information, p. 80 - 83 (2016/01/15)
Relying on the nucleophilicity of silanol for building up silicon-incorporated scaffold with an enantiopure tetrasubstituted carbon center remains elusive. In this report, asymmetric bromo-oxycyclization of olefinic silanol by using chiral anionic phase-transfer catalyst is described. This protocol provided a facile entry to a wide arrangement of enantiopure benzoxasilole in moderate to excellent enantioselectivities depending on the unique reactivity of bromine/N-benzyl-DABCO complex.
