1005500-77-5Relevant articles and documents
α-Imino Gold Carbenes from 1,2,4-Oxadiazoles: Atom-Economical Access to Fully Substituted 4-Aminoimidazoles
Zeng, Zhongyi,Jin, Hongming,Xie, Jin,Tian, Bing,Rudolph, Matthias,Rominger, Frank,Hashmi, A. Stephen K.
, p. 1020 - 1023 (2017)
A novel and atom-economical synthesis of fully substituted 4-aminoimidazoles via gold-catalyzed selective [3 + 2] annulation of 1,2,4-oxadiazoles with ynamides is reported. This protocol represents a new strategy to access α-imino gold carbenes, which corresponds to an unprecedented intermolecular transfer of N-acylimino nitrenes to ynamides. Moreover, the reaction proceeds with 100% atom economy, exhibits good functional group tolerance, and can be conducted in gram scale.
AgOTf-catalyzed reaction of sulfonyl hydrazones with ynamides led to stereoselective synthesis of α-amino alkenyl-substituted hydrazone derivatives
Cao, Ziping,Yan, Shikun,Zhao, Changyin,Sun, Xuejun,Tian, Laijin,Meng, Xin
, (2019)
A novel method for the synthesis of α-amino alkenyl-substituted hydrazone derivatives was disclosed through silver-catalyzed reaction of sulfonyl hydrazones with ynamides. The present method features mild conditions, high stereoselectivity and good yields. The proposed mechanism involves silver-mediated generation of a keteniminium ion intermediate to facilitate the stereoselective addition of hydrazones in the presence of K2CO3, while pyrazole ring could not be constructed under the current conditions.
Ring Expansion and 1,2-Migration Cascade of Benzisoxazoles with Ynamides: Experimental and Theoretical Studies
Vanjari, Rajeshwer,Dutta, Shubham,Prabagar,Gandon, Vincent,Sahoo, Akhila K.
, p. 4828 - 4836 (2019)
Demonstrated herein is an AuI-catalyzed annulation of sulfonyl-protected ynamides with substituted 1,2-benzisoxazoles for the synthesis of E-benzo[e][1,3]oxazine derivatives. The transformation involves the addition of benzisoxazole to the gold-activated ynamide, ring expansion of the benzisoxazole fragment to provide an α-imino vinylic gold intermediate, and 1,2-migration of the sulfonamide motif to the masked carbene center to deliver the respective ring-expanded benzo[e][1,3]oxazine of predominant E configuration. A trapping experiment justifies the participation of the α-imino masked gold carbene. DFT computations also support the hypothesized mechanism and rationalize the product stereoselectivity.
Er(OTf)3-catalyzed approach to 3-alkenylindoles through regioselective addition of ynamides and indoles
Liu, Yi-Wen,Ma, Rui-Jun,Si, Chang-Mei,Wang, Qiao-E,Wei, Bang-Guo
, (2020)
An efficient approach to access functionalized 3-alkenylindoles has been developed through Er(OTf)3-catalyzed addition of ynamides and indoles. A number of C-aryl substituted ynamides 7a-7k could react with indoles 6a-6s, affording the desired products 8aa-8sa, 8ab-8ak, 8bd, 8bk and 8tc in moderate to excellent yields with high regioselectivities.
Nickel-catalyzed regioselective hydroamination of ynamides with secondary amines
Si, Chang-Mei,Wei, Bang-Guo,Nie, Xiao-Di,Han, Xiao-Li,Sun, Jian-Ting,Lin, Guo-Qiang
, p. 3433 - 3443 (2021)
The first Ni(OTf)2-catalyzed hydroamination of ynamides 2 was developed by reacting with secondary amines (1 and 4). This protocol features excellent regioselectivity, a broad substrate scope of secondary aryl amines, and good functional group tolerance for ynamides. Using this method, a variety of substituted ethene-1,1- diamine compounds were prepared in moderate to excellent yields with high regioselectivities.
DIBENZOTHIOPHENE SALT AS ALKYNYLATING AND CYANATING AGENT
-
Paragraph 0092; 0051, (2021/08/27)
The present invention describes a new alkynylation and cyanation agent, as well as its preparation and use to introduce nitrile (cyano) or alkyne groups into chemical target molecules by means of an electrophilic reaction. To enable an electrophilic reaction, the chemical backbone of dibenzothiophene was used.
A Unified Approach for Divergent Synthesis of Heterocycles via TMSOTf-Catalyzed Formal [3+2] Cycloaddition of Electron-Rich Alkynes
Chen, Ping,Cao, Wei,Li, Xiangqian,Shi, Dayong
supporting information, p. 4789 - 4794 (2021/09/02)
We present a synthetic protocol for the construction of polysubstituted five-membered heterocycles via TMSOTf-catalyzed formal [3+2] cycloaddition of electron-rich alkynes, which features free from any metal, atom economy and water as the main by-product. Furthermore, alkenyl ether adduct has been verified as the key intermediate. Notably, by utilizing this approach, we can synthesize a broad range of polysubstituted furans, thiophenes and pyrroles, and extend this transformation to deliver fused-polyheterocycles. This reaction can be achieved on a gram scale and the corresponding products are intermediates for producing diverse potentially useful scaffolds. (Figure presented.).
