Carbene catalyzed C(sp³)–Cl activation of chlorinated solvents for benzyne chlorination

Abstract

An N-heterocyclic carbene (NHC) organocatalyzed benzyne chlorination reaction was reported. Chlorinated solvents, usually shown to be inert, were widely used in either carbene chemistry or benzyne chemistry. However, the combination...

Reactivity of free N-heterocyclic carbenes in dichloromethane

“…13 In contrast to bulky NHCs, which are synthesised by deprotonation of the corresponding imidazolium salts, 14 Me IPr is commonly obtained through reduction of the thiourea derivative with potassium metal. 15 Therefore, the [ Me IPrH] + cation was only obtained as decomposition product from metal complexes with Me IPr and only single crystal X-ray diffraction data without further properties has been reported for: [ 24,25 While halogenated hydrocarbons with weaker C-halide bonds are known to react under halogenation of NHCs either at the carbene-carbon atom or at the 3-and 4-position of the backbone of the imidazolium moiety, [25][26][27] no such reactions are known with dichloromethane. Considering dichloromethane is often one of the few possible solvents for ionic compounds, which is also available deuterated, we investigated the reaction of Me IPr with CH 2 Cl 2 in more detail.…”

“…This presumed decomposition is likely caused by deprotonation of CH 2 Cl 2 , which is related to reactions of bulky NHCs with CH 2 Cl 2 and CHCl 3 . 24,25 While halogenated hydrocarbons with weaker C–halide bonds are known to react under halogenation of NHCs either at the carbene–carbon atom or at the 3- and 4-position of the backbone of the imidazolium moiety, 25–27 no such reactions are known with dichloromethane. Considering dichloromethane is often one of the few possible solvents for ionic compounds, which is also available deuterated, we investigated the reaction of Me IPr with CH 2 Cl 2 in more detail.…”