298195-93-4Relevant articles and documents
DMSO/SOCl2-mediated C(sp2)-H amination: Switchable synthesis of 3-unsubstituted indole and 3-methylthioindole derivatives
Zhang, Jingran,Li, Xiaoxian,Li, Xuemin,Shi, Haofeng,Sun, Fengxia,Du, Yunfei
, p. 460 - 463 (2021/01/25)
The reaction of 2-alkenylanilines with SOCl2 in DMSO was found to selectively afford 3-unsubstituted indoles and 3-methylthioindoles. This switchable approach was found to be temperature-dependent: at room temperature, the reaction afforded 3-unsubstituted indoles through intramolecular cyclization and elimination; while at higher temperature, the reaction gave 3-methylthioindoles via further electrophilic methylthiolation.
Triple Mode of Alkylation with Ethyl Bromodifluoroacetate: N, or O-Difluoromethylation, N-Ethylation and S-(ethoxycarbonyl)difluoromethylation
Polley, Arghya,Bairy, Gurupada,Das, Pritha,Jana, Ranjan
supporting information, p. 4161 - 4167 (2018/09/21)
In this report, we have explored a triple mode of chemical reactivity of ethyl bromodifluoroacetate. Typically, bromodifluoroacetic acid has been used as a difluorocarbene precursor for difluoromethylation of soft nucleophiles. Here we have disclosed nucleophilicity and base dependent divergent chemical reactivity of ethyl bromodifluoroacetate. It furnishes lithium hydroxide and cesium carbonate promoted difluoromethylation of tosyl-protected aniline and electron-deficient phenols respectively. Interestingly, switching the base from lithium hydroxide to 4-N,N-dimethylamino pyridine (DMAP) tosyl-protected anilines afforded the corresponding N-ethylation product. Whereas, highly nucleophilic thiophenols furnished the corresponding S-carboethoxydifluoromethylation product via a rapid SN2 attack to the bromine atom prior to the ester hydrolysis. This mechanistic divergence was established through several control experiments. It was revealed that difluoromethylation reaction proceeds through a tandem in situ ester hydrolysis/decarboxylative-debrominative difluorocarbene formation and subsequent trapping by the soft nucleophile-NHTs or electron-deficient phenolic ?OH groups. In the presence of DMAP the hydrolysis of the ester is perturbed instead a nucleophilic attack at the ethyl moiety provides the N-ethylation product. Hence, besides the development of a practical base-promoted N-difluoromethylation of amines and electron-deficient phenols, divergent reactivity pattern of inexpensive and user-friendly ethyl bromodifluoroacetate has been explored. (Figure presented.).
Selenium-catalyzed oxidative c(sp2)-h amination of alkenes exemplified in the expedient synthesis of (Aza-)indoles
Ortgies, Stefan,Breder, Alexander
, p. 2748 - 2751 (2015/06/16)
A new selenium-catalyzed protocol for the direct, intramolecular amination of C(sp2)-H bonds using N-fluorobenzenesulfonimide as the terminal oxidant is reported. This method enables the facile formation of a broad range of diversely functionalized indoles and azaindoles derived from easily accessible ortho-vinyl anilines and vinylated aminopyridines, respectively. The procedure exploits the pronounced carbophilicity of selenium electrophiles for the catalytic activation of alkenes and leads to the formation of C(sp2)-N bonds in high yields and with excellent functional group tolerance.
