1485-98-9Relevant academic research and scientific papers
Hydrogen Bonding Networks Enable Br?nsted Acid-Catalyzed Carbonyl-Olefin Metathesis**
Anh To, Tuong,Pei, Chao,Koenigs, Rene M.,Vinh Nguyen, Thanh
, (2022/02/17)
Synthetic chemists have learned to mimic nature in using hydrogen bonds and other weak interactions to dictate the spatial arrangement of reaction substrates and to stabilize transition states to enable highly efficient and selective reactions. The activation of a catalyst molecule itself by hydrogen-bonding networks, in order to enhance its catalytic activity to achieve a desired reaction outcome, is less explored in organic synthesis, despite being a commonly found phenomenon in nature. Herein, we show our investigation into this underexplored area by studying the promotion of carbonyl-olefin metathesis reactions by hydrogen-bonding-assisted Br?nsted acid catalysis, using hexafluoroisopropanol (HFIP) solvent in combination with para-toluenesulfonic acid (pTSA). Our experimental and computational mechanistic studies reveal not only an interesting role of HFIP solvent in assisting pTSA Br?nsted acid catalyst, but also insightful knowledge about the current limitations of the carbonyl-olefin metathesis reaction.
Iron-Catalyzed Ring-Opening Reactions of Cyclopropanols with Alkenes and TBHP: Synthesis of 5-Oxo Peroxides
Lou, Chenhao,Wang, Xin,Lv, Leiyang,Li, Zhiping
, p. 7608 - 7612 (2021/10/02)
The ring opening of cyclopropanols is rarely used in multicomponent reactions. Herein we report the three-component reaction of cyclopropanols with alkenes and tert-butyl hydroperoxide (TBHP) catalyzed by an iron catalyst. This protocol enables the incorporation of both the β-carbonyl fragment and a peroxy unit across the C=C double bond regioselectively, thus allowing an efficient, facile access to 5-oxo peroxides. Modification of the biologically active molecules and various downstream derivatizations of the peroxides are also demonstrated.
Carbonyl-Olefin Metathesis Catalyzed by Molecular Iodine
Tran, Uyen P. N.,Oss, Giulia,Breugst, Martin,Detmar, Eric,Pace, Domenic P.,Liyanto, Kevin,Nguyen, Thanh V.
, p. 912 - 919 (2019/01/14)
The carbonyl-olefin metathesis reaction could facilitate rapid functional group interconversion and allow construction of complicated organic structures. Herein, we demonstrate that elemental iodine, a very simple catalyst, can efficiently promote this chemical transformation under mild reaction conditions. Our mechanistic studies revealed intriguing aspects of the activation mode via molecular iodine and the iodonium ion that could change the previously established perception of catalyst and substrate design for the carbonyl-olefin metathesis reaction.
Br?nsted Acid-Catalyzed Carbonyl-Olefin Metathesis inside a Self-Assembled Supramolecular Host
Catti, Lorenzo,Tiefenbacher, Konrad
, p. 14589 - 14592 (2018/01/27)
Carbonyl–olefin metathesis represents a powerful yet underdeveloped method for the formation of carbon–carbon bonds. So far, no Br?nsted acid based method for the catalytic carbonyl–olefin metathesis has been described. Herein, a cocatalytic system based on a simple Br?nsted acid (HCl) and a self-assembled supramolecular host is presented. The developed system compares well with the current benchmark catalyst for carbonyl–olefin metathesis in terms of substrate scope and yield of isolated product. Control experiments provide strong evidence that the reaction proceeds inside the cavity of the supramolecular host. A mechanistic probe indicates that a stepwise reaction mechanism is likely.
Base-Promoted/Gold-Catalyzed Intramolecular Highly Selective and Controllable Detosylative Cyclization
Zhu, Chenghao,Qiu, Lin,Xu, Guangyang,Li, Jian,Sun, Jiangtao
, p. 12871 - 12875 (2015/09/07)
A highly selective, controllable and synthetically useful base-promoted intramolecular detosylative cyclization of bis-N-tosylhydrazones has been achieved, affording N-containing heterocycles and cyclic olefins under transition-metal-free or gold-catalyzed procedures, respectively. Moreover, an effective and practical metal-free or gold-catalyzed approach to synthesize polycyclic aromatic compounds is also reported. Basic cyclizations: A highly selective, controllable, and synthetically useful base-promoted intramolecular detosylative cyclization of bis-N-tosylhydrazones affords N-containing heterocycles and cyclic olefins under transition-metal-free or gold-catalyzed procedures, respectively. Moreover, an effective and practical metal-free or gold-catalyzed approach to synthesize polycyclic aromatic compounds is also reported.
Rhodium(II)-catalyzed cyclization of bis(N-tosylhydrazone)s: An efficient approach towards polycyclic aromatic compounds
Xia, Ying,Liu, Zhenxing,Xiao, Qing,Qu, Peiyuan,Ge, Rui,Zhang, Yan,Wang, Jianbo
, p. 5714 - 5717 (2012/07/28)
Ahead of the PAC: Polycyclic aromatic compounds (PACs) can be easily accessed by the combination of Suzuki-Miyaura cross-coupling and a [Rh 2(OAc)4]-catalyzed carbene reaction using easily available bis(N-tosylhydrazone)s as intermediates (see scheme; Ts=4-toluenesulfonyl). Copyright
Molecular engineering of the glass transition: Glass-forming ability across a homologous series of cyclic stilbenes
Ping, Wen,Paraska, Daniel,Baker, Robert,Harrowell, Peter,Angell, C. Austen
experimental part, p. 4696 - 4702 (2011/06/09)
We report on the glass-forming abilities of the homologous series 1,2-diphenylcyclo-butene, pentene, hexene and heptene-a series that retains the cis-phenyl configuration characteristic of the well-studied glass former, o-terphenyl. We find that the glass
Evidence for the formation of a new five-membered ring cyclic allene: Generation of 1-cyclopenta-1,2-dien-1-ylbenzene
Ceylan, Mustafa,Yalcin, Seher,Secen, Hasan,Suetbeyaz, Yasar,Balci, Metin
, p. 21 - 23 (2007/10/03)
Treatment of 1-(2-iodocyclopent-1-en-1-yl) benzene (13), dissolved in benzene, with potassium t-butoxide resulted in the formation of 1-(2-phenylcyclopent-1-en-1-yl) benzene (15) and 1-cyclopent-1-en-1-yl benzene (5) in a ratio of 1:1.
Base-Induced Proton Tautomerism in the Primary Photocyclization Product of Stilbenes
Somers, J. B. M.,Couture, A.,Lablache-Combier, A.,Laarhoven, W. H.
, p. 1387 - 1394 (2007/10/02)
The mechanism of the photoformation of 1,4-dihydrophenanthrenes (1,4-DHP) and 9,10-dihydrophenanthrenes from 1,2-diarylethylenes in amine solution is clarified by demonstrating that the amine reacts as a base with the initially formed 4a,4b-dihydrophenanthrene.The predominant formation of 1,4-DHP from stilbene is ascribed to an easy proton transfer from C(4b) to C(4) in 4a,4b-DHP via a deprotonation/protonation step, in which the amine operates as the transferring agent.The product formation in basic methanolic solutions proceeds with another mechanism or with less selectivity.When propyl thiolate, having a weak hydrogen-bonding capability, is used as the base, the solvent-mediated protonation in the deprotonation/protonation step occurs exclusively at C(9) and leads eventually to 9,10-DHP.When the stronger base sodium methoxide is used, solvent-mediated protonation proceeds rather unselectively at C(2), C(4), and C(9) and causes the ultimate formation of a mixture of 1,2-, 1,4-, and 9,10-DHP.Deuteration experiments indicate that 1,2- and 3,4-DHP are intermediates in the formation of 1,4-DHP (Scheme VII).The former compounds isomerize photochemically in the presence of a base.Larger diarylethylenes give only compounds analogous to 9,10-DHP.
