1198-34-1Relevant academic research and scientific papers
Palladium-catalyzed regioselective arylation of silyloxy compounds with triarylantimony diacetates
Kang, Suk-Ku,Ryu, Hyung-Chul,Honge, Young-Taek
, p. 3350 - 3351 (2000)
The regioselective arylation of silyloxy compounds with triarylantimony diacetates was performed by using palladium catalysts. The silyl enol ether, silyl dienol ethers and silyl oxycyclopropane were arylated in the presence of a palladium catalysts with triarylantimony(V) diacetates under mild conditions. The results showed that the given method had the advantage of mild conditions which involved the use of PdCl2 at room temperature even in the presence of water.
Fluorotetraphenylbismuth: A new reagent for efficient regioselective α-phenylation of carbonyl compounds
Ooi, Takashi,Goto, Ryoji,Maruoka, Keiji
, p. 10494 - 10495 (2003)
Synthesis and X-ray crystallographic characterization of fluorotetraphenylbismuth (1) has been achieved for the first time, revealing that the bismuth center of 1 adopts a distorted trigonal bipyramidal geometry with three ipso carbons at the equatorial sites and one ipso carbon and fluorine atom at the apical sites. Contrary to the previous common understanding of this type of organobismuth(V) compound, 1 was found to be thermally stable, maintaining its amphiphilic property. Hence, 1 can be used as an off-the-shelf reagent in organic synthesis, and its utility has been clearly demonstrated in applications to the efficient α-phenylation of ketones and esters. For instance, simple mixing of 1 and 1-trimethylsiloxy-3,4-dihydronaphthalene in THF at -40 °C and stirring at room temperature for 10 min gave rise to 2-phenyl-1-tetralone almost quantitatively without formation of the polyphenylated products. In addition to the generality of this method, applicability of our approach to the selective α-alkenylation of carbonyl compounds was also demonstrated by the use of fluoro(2-phenylethenyl)tris(p-tolyl)bismuth (2) as a representative reagent. These results imply the vast potential of organobismuth(V) compounds of type 1 and 2 as useful precursors of a wide variety of pentavalent organobismuth compounds based on the utilization of the eminent fluorine-silicon interaction or the inherent basicity of the fluorine atom. Copyright
Diversity-Oriented Synthesis of Bioactive Azaspirocycles
Lepovitz, Lance T.,Martin, Stephen F.
, (2019)
A collection of novel azaspirocyclic β-arylethylamines was prepared in good yield and excellent diastereoselectivity by an expedient strategy that features condensation of a cyclic ketone with an amino allylsilane and a tandem aza-Sakurai cyclization to generate several different spirocyclic N-heterocycles. Subsequent elaboration of the spirocyclic scaffold was achieved via Pictet-Spengler cyclizations, Suzuki cross-coupling reactions, N-functionalizations, and olefin refunctionalization reactions to create a diverse library of compounds, several of which have nanomolar affinity for the sigma 1 receptor and transmembrane protein 97 (TMEM97).
Deciphering Reactivity and Selectivity Patterns in Aliphatic C-H Bond Oxygenation of Cyclopentane and Cyclohexane Derivatives
Martin, Teo,Galeotti, Marco,Salamone, Michela,Liu, Fengjiao,Yu, Yanmin,Duan, Meng,Houk,Bietti, Massimo
supporting information, p. 9925 - 9937 (2021/06/30)
A kinetic, product, and computational study on the reactions of the cumyloxyl radical with monosubstituted cyclopentanes and cyclohexanes has been carried out. HAT rates, site-selectivities for C-H bond oxidation, and DFT computations provide quantitative information and theoretical models to explain the observed patterns. Cyclopentanes functionalize predominantly at C-1, and tertiary C-H bond activation barriers decrease on going from methyl- and tert-butylcyclopentane to phenylcyclopentane, in line with the computed C-H BDEs. With cyclohexanes, the relative importance of HAT from C-1 decreases on going from methyl- and phenylcyclohexane to ethyl-, isopropyl-, and tert-butylcyclohexane. Deactivation is also observed at C-2 with site-selectivity that progressively shifts to C-3 and C-4 with increasing substituent steric bulk. The site-selectivities observed in the corresponding oxidations promoted by ethyl(trifluoromethyl)dioxirane support this mechanistic picture. Comparison of these results with those obtained previously for C-H bond azidation and functionalizations promoted by the PINO radical of phenyl and tert-butylcyclohexane, together with new calculations, provides a mechanistic framework for understanding C-H bond functionalization of cycloalkanes. The nature of the HAT reagent, C-H bond strengths, and torsional effects are important determinants of site-selectivity, with the latter effects that play a major role in the reactions of oxygen-centered HAT reagents with monosubstituted cyclohexanes.
Enantioselective Radical Ring-Opening Cyanation of Oxime Esters by Dual Photoredox and Copper Catalysis
Chen, Jun,Wang, Peng-Zi,Lu, Bin,Liang, Dong,Yu, Xiao-Ye,Xiao, Wen-Jing,Chen, Jia-Rong
supporting information, p. 9763 - 9768 (2019/11/29)
Catalytic enantioselective chemical reactions involving highly reactive radical species remain largely unexplored. We report herein for the first time a novel enantioselective radical ring-opening cyanation of redox-active oxime esters by dual photoreodox
Identification and Preclinical Evaluation of the Bicyclic Pyrimidine γ-Secretase Modulator BMS-932481
Boy, Kenneth M.,Guernon, Jason M.,Zuev, Dmitry S.,Xu, Li,Zhang, Yunhui,Shi, Jianliang,Marcin, Lawrence R.,Higgins, Mendi A.,Wu, Yong-Jin,Krishnananthan, Subramaniam,Li, Jianqing,Trehan, Ashok,Smith, Daniel,Toyn, Jeremy H.,Meredith, Jere E.,Burton, Catherine R.,Kimura, S. Roy,Zvyaga, Tatyana,Zhuo, Xiaoliang,Lentz, Kimberley A.,Grace, James E.,Denton, Rex,Morrison, John S.,Mathur, Arvind,Albright, Charles F.,Ahlijanian, Michael K.,Olson, Richard E.,Thompson, Lorin A.,Macor, John E.
supporting information, p. 312 - 317 (2019/03/08)
A triazine hit identified from a screen of the BMS compound collection was optimized for potency, in vivo activity, and off-target profile to produce the bicyclic pyrimidine γ-secretase modulator BMS-932481. The compound showed robust reductions of Aβsub
Copper-catalyzed ring-opening C(sp3)-N coupling of cycloketone oxime esters: Access to 1°, 2° and 3° alkyl amines
Tian, Li,Gao, Shuangqiu,Wang, Rui,Li, Yang,Tang, Chunlin,Shi, Lili,Fu, Junkai
supporting information, p. 5347 - 5350 (2019/05/10)
A novel copper-catalyzed C(sp3)-N coupling of cycloketone oxime esters with nitrogen nucleophiles has been realized. All of the N-aryl/alkylanilines, anilines and benzophenone imine could be employed in this protocol to produce a variety of 1°, 2° and 3° alkyl amines in one or two steps. These resultant cyano-containing alkyl amines were proven to be versatile synthetic building blocks in a variety of chemical transformations.
Photocatalytic carbanion generation from C-H bonds-reductant free Barbier/Grignard-type reactions
Berger, Anna Lucia,Donabauer, Karsten,K?nig, Burkhard
, p. 10991 - 10996 (2019/12/28)
We report a redox-neutral method for the generation of carbanions from benzylic C-H bonds in a photocatalytic Grignard-type reaction. The combination of photo- and hydrogen atom transfer (HAT) catalysis enables the abstraction of a benzylic hydrogen atom, generating a radical intermediate. This radical is reduced in situ by the organic photocatalyst to a carbanion, which is able to react with electrophiles such as aldehydes or ketones, yielding homobenzylic secondary and tertiary alcohols.
Cu-Catalyzed Redox-Neutral Ring Cleavage of Cycloketone O-Acyl Oximes: Chemodivergent Access to Distal Oxygenated Nitriles
Ai, Wenying,Liu, Yaqian,Wang, Qian,Lu, Zhonglin,Liu, Qiang
supporting information, p. 409 - 412 (2018/01/27)
A chemodivergent copper-catalyzed ring opening of cycloketone oximes via radical-mediated C-C bond cleavage under redox-neutral conditions is described. This method allows the divergent synthesis of γ- and δ-acyloxylated, alkoxylated, and hydroxylated nitriles while avoiding the use of toxic cyanide reagents. Moreover, these reactions proceed under very mild conditions with good functional group tolerance. Notably, ring-opening reactions of the less-strained substrate cyclopentanone oxime also proceeded well under the established conditions.
Photoinduced C—C Bond Cleavage and Oxidation of Cycloketoxime Esters
Zhao, Binlin,Tan, Hui,Chen, Cheng,Jiao, Ning,Shi, Zhuangzhi
supporting information, p. 995 - 999 (2018/09/25)
A novel structural reorganization of cycloketoxime esters beyond the traditional Beckmann rearrangement process has been established to build cyano-containing ketones in the presence of photocatalyst. This novel transformation is remarkable with selective C—C bond cleavage and an oxidation process enabled by DMSO used as the solvent, oxidant, and oxygen source avoiding acid, base and toxic cyanide salts as the cyano source. Further applications in late-stage modification of complex and chiral molecules have also been reported.
