41252-83-9Relevant academic research and scientific papers
Ni/Photoredox-Catalyzed Enantioselective Cross-Electrophile Coupling of Styrene Oxides with Aryl Iodides
Lau, Sii Hong,Borden, Meredith A.,Steiman, Talia J.,Wang, Lucy S.,Parasram, Marvin,Doyle, Abigail G.
supporting information, p. 15873 - 15881 (2021/10/12)
A Ni/photoredox-catalyzed enantioselective reductive coupling of styrene oxides and aryl iodides is reported. This reaction affords access to enantioenriched 2,2-diarylalcohols from racemic epoxides via a stereoconvergent mechanism. Multivariate linear regression (MVLR) analysis with 29 bioxazoline (BiOx) and biimidazoline (BiIm) ligands revealed that enantioselectivity correlates with electronic properties of the ligands, with more electron-donating ligands affording higher ee's. Experimental and computational mechanistic studies were conducted, lending support to the hypothesis that reductive elimination is enantiodetermining and the electronic character of the ligands influences the enantioselectivity by altering the position of the transition state structure along the reaction coordinate. This study demonstrates the benefits of utilizing statistical modeling as a platform for mechanistic understanding and provides new insight into an emerging class of chiral ligands for stereoconvergent Ni and Ni/photoredox cross-coupling.
Ni-Catalyzed Formal Cross-Electrophile Coupling of Alcohols with Aryl Halides
Lin, Quan,Ma, Guobin,Gong, Hegui
, p. 14102 - 14109 (2021/11/20)
Direct coupling of unactivated alcohols remains a challenge in current synthetic chemistry. We herein demonstrate a strategy building upon in situ halogenation/reductive coupling of alcohols with aryl halides to forge Csp2-Csp3 bonds. The combination of 2-chloro-3-ethylbenzo[d]oxazol-3-ium salt (CEBO) and TBAB as the mild bromination reagents enables rapid transformation of a wide range of alcohols to their bromide counterparts within one to 5 min in CH3CN and DMF, which is compatible with the Ni-catalyzed cross-electrophile coupling conditions in the presence of a chemical reductant. The present method is suitable for arylation of a myriad of structurally complex alcohols with no need for prepreparation of alkyl halides. More importantly, the mild and kinetically rapid bromination process has shown good selectivity in the bromination/arylation of symmetric diols and less sterically hindered hydroxyl groups in polyols, thus offering promise for selective functionalization of diols and polyols without laborious protecting/deprotecting operations. The practicality of this work is also evident in the arylation of a number of carbohydrates, drug compounds, and naturally occurring alcohols.
Use of allylzinc halide as a source of halide: Differential addition of nucleophiles to Ts-aziridines and aldehydes under similar reaction conditions
Chatterjee, Rana,Samanta, Satyajit,Mukherjee, Anindita,Santra, Sougata,Zyryanov, Grigory V.,Majee, Adinath
supporting information, p. 276 - 283 (2019/01/04)
We have observed that the allylic zinc halide under identical reaction conditions acts in different modes for different electrophiles. For Ts-aziridines the halide part of the allylic halide has been introduced as a nucleophile and for the carbonyl compou
LiBr/β-CD/IBX/H2O-DMSO: A new approach for one-pot biomimetic regioselective ring opening of chalcone epoxides to bromohydrins and conversion to 1,2,3-triketones
Verma, Nishant,Kumar, Sumit,Ahmed, Naseem
, p. 1110 - 1120 (2017/05/25)
Highly regioselective ring cleavage of chalcone epoxides to bromohydrins has been carried out in good yields with LiBr in the presence of β-CD using DMSO-H2O as solvent system. The ring-opened product, i.e., bromohydrin, was well adapted to IBX-mediated oxidation in such a fashion that the bromohydrins are transformed to their corresponding 1,2,3-triketones in moderate-to-good yields in one pot.
C-ON bond homolysis of alkoxyamines: When too high polarity is detrimental
Nkolo, Paulin,Audran, Gérard,Bikanga, Raphael,Brémond, Paul,Marque, Sylvain R. A.,Roubaud, Valérie
, p. 6167 - 6176 (2017/08/02)
Throughout the last decade, the effect of electron withdrawing groups (EWGs) has been known to play a role-minor or moderate depending on the nitroxyl fragment R1R2NO-in the change in the homolysis rate constant (kd) for C-ON bond homolysis in alkoxyamines (R1R2NOR). It has been shown that the effect of EWGs on kd is described by a linear relationship with the electrical Hammett constant σI. Since then, linear multi-parameter relationships f(σRS,ν,σI) have been developed to account for the effects involved in the changes in kd, which are the stabilization of the released radical (σRS) and the bulkiness (ν) and polarity (σI) of the alkyl fragment. Since a decade ago, new results have been published highlighting the limits of such correlations. In this article, previous multi-parameter linear relationships are amended using a parabolic model, i.e. (σI,nitroxide - σI,alkyl)2, to describe the effect of EWGs in the alkyl fragment on kd. In contrast to previous studies, these improved linear multi-parameter relationships f(σRS,ν,ΔσI2) are able to account for the presence of several EWGs on the alkyl fragment, R. An unexpectedly strong solvent effect-a ca. 1500-fold increase in kd-from tert-butylbenzene to the water/methanol mixture is also observed for 3-((2,2,6,6-tetramethylpiperidin-1-yl)oxyl)pentane-2,4-dione 1b in comparison to a ca. 5-fold increase in kd that is generally observed.
A Versatile Iridium(III) Metallacycle Catalyst for the Effective Hydrosilylation of Carbonyl and Carboxylic Acid Derivatives
Corre, Yann,Rysak, Vincent,Trivelli, Xavier,Agbossou-Niedercorn, Francine,Michon, Christophe
supporting information, p. 4820 - 4826 (2017/09/07)
A versatile iridium(III) metallacycle catalysed rapidly and selectively the reduction of a large array of challenging esters and carboxylic acids as well as various ketones and aldehydes. The reactions proceeded in high yields at room temperature by hydrosilylation followed by desilylation. Although the reactions of various aldehydes and ketones resulted exclusively in alcohols, the hydrosilylation of esters led to alcohols or ethers, depending on the type of substrate. Regarding the carboxylic acids, again the nature of the reagent controlled the outcome of the hydrosilylation reaction, either alcohols or aldehydes being formed.
Trihaloisocyanuric Acid/Triphenylphosphine: An Efficient System for Regioselective Conversion of Epoxides into Vicinal Halohydrins and Vicinal Dihalides under Mild Conditions
De Andrade, Vitor S. C.,De Mattos, Marcio C. S.
, p. 1381 - 1388 (2016/05/19)
A new synthetic method has been developed for the regioselective conversion of epoxides to vicinal chloro-/bromohydrins and vicinal dihalides by reaction with the system trihaloisocyanuric acid/tri?phenylphosphine in acetonitrile under mild and neutral conditions. The reactions proceed smoothly in high yield at room temperature and at reflux, respectively, over a short time.
Design, synthesis, and biological evaluation of crenatoside analogues as novel influenza neuraminidase inhibitors
Chen, Bao-Long,Wang, Ya-Jing,Guo, Hong,Zeng, Guang-Yao
, p. 199 - 205 (2016/01/16)
Natural products, especially derived from TCMH, have been found to exert antiviral effects against influenza virus. Crenatoside, a phenylethanoid glycoside from Pogostemon cablin Benth, which has been shown as a novel effective NA inhibitor previously, is considered as the leading compound for our further SARs studies. This work presented design, synthesis of novel crenatoside analogues from readily available d-Glucose and l-rhamnose in a convergent manner. Furthermore, their biological activities and SARs were also investigated. Especially, compound 2 h showed impressive IC50 = 27.77 μg/mL against NAs, which is 3 folds more potent than the leading compound crenatoside (IC50 = 89.81 μg/mL). These results would promise their therapeutic potential for influenza disease.
Direct halogenation of alcohols with halosilanes under catalyst- and organic solvent-free reaction conditions
Ajvazi, Njomza,Stavber, Stojan
supporting information, p. 2430 - 2433 (2016/05/19)
A chemoselective method for the direct halogenation of different types of alcohols with halosilanes under catalyst- and solvent-free reaction conditions (SFRC) is reported. Various primary, secondary and tertiary benzyl alcohols and tertiary alkyl alcohols were directly transformed to the corresponding benzyl and alkyl halides, respectively, using chlorotrimethylsilane (TMSCl) and bromotrimethylsilane (TMSBr).
Synthesis of diversely functionalised 2,2-disubstituted oxetanes: Fragment motifs in new chemical space
Davis, Owen A.,Croft, Rosemary A.,Bull, James A.
supporting information, p. 15446 - 15449 (2015/10/20)
Di-, tri- and tetra-substituted oxetane derivatives with combinations of ester, amide, nitrile, aryl, sulfone and phosphonate substituents are prepared as fragments or building blocks for drug discovery. The synthesis of these novel oxetane functional groups, in new chemical space, is achieved via rhodium-catalysed O-H insertion and C-C bond forming cyclisation.
