14630-42-3Relevant academic research and scientific papers
α-Silicon- and α-alkynyl-substituted vinyl cations
Schiavelli, Melvyn D.,Jung, Dorothy M.,Vaden, Anne Keller,Stang, Peter J.,Fisk, Thomas E.,Morrison, David S.
, p. 92 - 95 (1981)
The solvolytic reactivity of a number of silicon- and alkynyl-substituted vinyl triflates was investigated in aqueous ethanol.Activation parameters and solvent m values were determined for all subtrates.Relative rate data show that the Me3Si group is accelerating and hence stabilizing relative to hydrogen but destabilizing relative to a t-Bu group.The α-ethynyl substituent causes a rate decrease compared to a methyl group despite its ?-donating resonance ability.These results are discussed.
Ynonylation of Acyl Radicals by Electroinduced Homolysis of 4-Acyl-1,4-dihydropyridines
Luo, Xiaosheng,Wang, Ping
supporting information, p. 4960 - 4965 (2021/07/20)
Herein we report the conversion of 4-Acyl-1,4-dihydropyridines (DHPs) into ynones under electrochemical conditions. The reaction proceeds via the homolysis of acyl-DHP under electron activation. The resulting acyl radicals react with hypervalent iodine(III) reagents to form the target ynones or ynamides in acceptable yields. This mild reaction condition allows wider functionality tolerance that includes halides, carboxylates, or alkenes. The synthetic utility of this methodology is further demonstrated by the late-stage modification of complex molecules.
γ-Carboline synthesis enabled by Rh(iii)-catalysed regioselective C-H annulation
Jiang, Bo,Jia, Jingwen,Sun, Yufei,Wang, Yichun,Zeng, Jing,Bu, Xiubin,Shi, Liangliang,Sun, Xiaoying,Yang, Xiaobo
supporting information, p. 13389 - 13392 (2020/11/10)
A redox-neutral Rh(iii)-catalyzed C-H annulation of indolyl oximes was developed. Relying on the use of various alkynyl silanes as the terminal alkyne surrogates, the reaction exhibited a reverse regioselectivity, thus giving an exclusive and easy way for the synthesis of a wide range of substituent free γ-carbolines at C3 position with high efficiency. Deuterium-labelling experiments and kinetic analysis have preliminarily shed light on the working mode of this catalytic system. This journal is
“Doubly Orthogonal” Labeling of Peptides and Proteins
Tessier, Romain,Ceballos, Javier,Guidotti, Nora,Simonet-Davin, Raphael,Fierz, Beat,Waser, Jerome
supporting information, p. 2243 - 2263 (2019/08/08)
Herein, we report a cysteine bioconjugation methodology for the introduction of hypervalent iodine compounds onto biomolecules. Ethynylbenziodoxolones (EBXs) engage thiols in small organic molecules and cysteine-containing peptides and proteins in a fast and selective addition onto the alkynyl triple bond, resulting in stable vinylbenziodoxolone hypervalent iodine conjugates. The conjugation occurs at room temperature in an open flask under physiological conditions. The use of an azide-bearing EBX reagent enables a “doubly orthogonal” functionalization of the bioconjugate via strain-release-driven cycloaddition and Suzuki-Miyaura cross-coupling of the vinyl hypervalent iodine bond. We successfully applied the methodology on relevant and complex biomolecules, such as histone proteins. Through single-molecule experiments, we illustrated the potential of this doubly reactive bioconjugate by introducing a triplet-state quencher close to a fluorophore, which extended its lifetime by suppressing photobleaching. This work is therefore expected to find broad applications for peptide and protein functionalization. Understanding the molecular basis of life is essential in the search for new medicines. Chemical biology develops molecular tools for studying biological processes, setting the basis for new diagnostics and therapeutics, and relies heavily on the ability to selectively modify biomolecules. Two approaches have been especially fruitful: (1) selective modification of natural biomolecules and (2) selective reaction between non-natural functionalities in the presence of biomolecules (the so-called orthogonal bioconjugation). In our work, we contribute to both by transferring highly reactive hypervalent iodine reagents to cysteine residues in proteins and peptides. The obtained bioconjugates retain the reactive hypervalent bonds, which can be selectively functionalized via a metal-mediated reaction. Combined with a traditional azide tag, our approach allows a doubly orthogonal functionalization of biomolecules and is hence expected to be highly useful in chemical biology. Chemical biology develops molecular tools for studying biological processes, setting the basis for new diagnostics and therapeutics, and relies heavily on the ability to modify selectively biomolecules. In our work, we introduce hypervalent iodine bonds into peptides and proteins, via functionalization of cysteine, by using unique cyclic reagents developed in our group. The hypervalent bond can then be selectively modified in the presence of both natural and synthetic functional groups, opening new opportunities for applications in chemical biology.
One-pot, three-component arylalkynyl sulfone synthesis
Chen, C. Chun,Waser, Jerome
supporting information, p. 736 - 739 (2015/03/05)
A one-pot three-component protocol for the preparation of arylsulfonyl alkynes through the reaction of ethynyl-benziodoxolone (EBX) reagents, DABSO (DABCO?·SO2), and either organomagnesium reagents or aryl iodides with a palladium catalyst is r
Ethynyl benziodoxolones for the direct alkynylation of heterocycles: Structural requirement, improved procedure for pyrroles, and insights into the mechanism
Brand, Jonathan P.,Chevalley, Clara,Scopelliti, Rosario,Waser, Jerome
supporting information; experimental part, p. 5655 - 5666 (2012/06/01)
This report describes a full study of the gold-catalyzed direct alkynylation of indoles, pyrroles, and thiophenes using alkynyl hypervalent iodine reagents, especially the study of the structural requirements of alkynyl benziodoxolones for an efficient acetylene transfer to heterocycles. An improved procedure for the alkynylation of pyrroles using pyridine as additive is also reported. Nineteen alkynyl benziodoxol(on)es were synthesized and evaluated in the direct alkynylation of indoles and/or thiophenes. Bulky silyl groups as acetylene substituents were optimal. Nevertheless, transfer of aromatic acetylenes to thiophene was achieved for the first time. An accelerating effect of a methyl substituent in both the 3-and 6-position of triisopropylsilylethynyl-1,2-benziodoxol-3(1H)-one (TIPS-EBX) on the reaction rate was observed. Competitive experiments between substrates of different nucleophilicity, deuterium labeling experiments, as well as the regioselectivity observed are all in agreement with electrophilic aromatic substitution. Gold(III) 2-pyridinecarboxylate dichloride was also an efficient catalyst for the reaction. Investigations indicated that gold(III) could be eventually reduced to gold(I) during the process. As a result of these investigations, a π activation or an oxidative mechanism are most probable for the alkynylation reaction.
Exploring skeletal diversity via ring contraction of glycal-derived scaffolds
Yeager, Adam R.,Min, Geanna K.,Porco Jr., John A.,Schaus, Scott E.
, p. 5065 - 5068 (2007/10/03)
(Chemical Equation Presented) Aryl ether C-glycoside scaffolds have been prepared from tri-O-acetyl-D-glucal by C-glycosylation followed by allylic substitution with phenols mediated by Pd(0). The aryl ethers were subjected to either [3,3]-sigmatropic rea
Unique σ-bond metathesis of silylalkynes promoted by an ansa-dimethylsilyl and oxo-bridged uranium metallocene
Wang, Jiaxi,Gurevich, Ylia,Botoshansky, Mark,Eisen, Moris S.
, p. 9350 - 9351 (2007/10/03)
The tetrachloride salt of uranium reacts with 1 equiv of the lithium ligand Li2[(C5Me4)2SiMe2] in DME to form the complex [η5-(C5Me4)2SiMe2]UCl2·2LiCl·2DME (1), which undergoes a rapid hydrolysis in toluene to yield the dimeric bridged monochloride, monooxide complex [{[η5-(C5Me4)2SiMe2]UCl}2(μ-O)(μ-Cl)?Li?1/2DME]2 (2). Metathesis of 2 with BuLi in DME gives the mono-bridged dibutyl complex {[η5-(C5Me4)2SiMe2]UBu}2(μ-O) (3). Complex 2 was characterized by solid-state X-ray analysis. Complex 3 was found to be an active catalyst for the disproportionation metathesis of TMSC≡CH (TMS = SiMe3) and the cross-metathesis of TMSC≡CH or TMSC≡CTMS with various terminal alkynes. The metathesis of TMSC≡CH gives TMSC≡CTMS and HC≡CH, whereas the cross-metathesis of TMSC≡CH or TMSC≡CTMS with terminal alkynes (RC≡CH) yields TMSC≡CTMS, TMSC≡CR, and HC≡CH. In addition, TMSC≡CCH3 also was found to react with tBuC≡CH, yielding TMSC≡CBut and CH3C≡CH. A plausible mechanism for the catalytic process is presented. Copyright
A simple synthesis of B-2-(1-trimethylsilyl-1-alkyl)-1,3,2-dioxaborinanes. Isolation and selective oxidation to 1-trimethylsilyl-1-alkanols
Bhat, Narayan G.,Garza, Amanda
, p. 6833 - 6835 (2007/10/03)
(Z)-1-Trimethylsilyl-1-alkenes easily prepared by the hydroboration of the corresponding 1-trimethylsilyl-1-alkynes followed by protonolysis with acetic acid, readily react with dibromoborane-methyl sulfide complex in dichloromethane for 6 h. The resulting solution is then treated with 1, 3-propane diol in a 1:1 mixture of dichloromethane and n-pentane at 0°C for half an hour to provide the corresponding gem-dimetalloalkanes containing boron and silicon. These alpha-trimethylsilylalkylboronate esters are purified by vacuum distillation in high yields (72-84%) and the structures of these novel intermediates are further confirmed by selective oxidation with alkaline hydrogen peroxide to provide the corresponding alcohols containing trimethylsilyl group.
Synthesis of internal acetylenes from vinylic tellurides
Terao, Jun,Kambe, Nobuaki,Sonoda, Noboru
, p. 5511 - 5512 (2007/10/03)
Vinylic tellurides were prepared by carbotelluration of acetylenes under light. The subsequent oxidation with sodium hypochlorite followed by pyrolysis gave internal acetylenes in good yields. Combination of these reactions provides a useful method for introduction of alkyl groups to terminal acetylenes.
