Methoxyalky 1-funktionalisierte 2,3-Dihy droimidazol-2-ylidene [1] / Methoxyalkyl Functionalized 2,3-Dihydroimidazol-2-ylidenes [1]

Abstract

The 2,3-dihydro-l,3-di(methoxyalkyl)imidazol-2-ylidenes are obtained from the correspon ding cyclic thioureas and potassium. With CS2, the imidazolium dithiocarboxylates are formed. The results of X-ray structure determinations of two of these products are reported.

Crystal structure of 1,3-dicyclohexyl-4,5-dimethyl-1H-imidazol-3-ium-2-carbodithioate chloroform monosolvate

“…The formation of stable 1.3-dicyclohexyl-4.5-dimethylimidazol-2-ylidene adducts confirmed the previous approach about nucleophilic character of N-heterocyclic carbenes (Kuhn et al, 1994. The title compound, crystallized in the zwitterion form, Fig. 1 129.54 (6)°] is similar to that in the structure of Et 3 PCS 2 (Margulis & Tempelton, 1962) and are also very close to the bond lengths S1-C1, S2-C1 1.670 (5) Å] in IMCS 2 (Kuhn et al, 1999). Parallel to this, the expansion of the bond angle S1-C1-S2 [129.54 (6)°] and the reduction of the angle N2-C2-N1 [108.8 (3)°] were observed.…”

“…For the properties and uses of heterocyclic carbenes, see: Kuhn & Al-Sheikh (2005); Kuhn et al (1995Kuhn et al ( , 1999; Mallah et al (2009); Margulis & Tempelton (1962). For the structures of similar compounds, see: Winberg & Coffman (1965); Kuhn et al (1994).…”

Betaine Adducts of N‐Heterocyclic Carbenes: Synthesis, Properties, and Reactivity

“…[34] The authors later complemented this study by introducing alkoxy-terminated alkyl chains at the heterocycle 1,3-positions [R = (CH 2 ) 2 OMe or (CH 2 ) 3 OMe]. [35] Their methodology was further exploited by Enders and co-workers in 1996 to prepare the CS 2 adduct of 1,3,4-triphenyl-4,5-dihydro-1H-1,2,4-triazol-5-ylidene [Equation (8)]. [36] (7) (8) Synthesis of a 1,3-dixylylimidazolium-2-dithiocarboxylate with silylated alkynyl functional groups on its 4,5-positions was accomplished by Faust and Göbelt in 2000 using a similar procedure [Equation (9)].…”

Synthesis of novel synthetic intermediates from the reaction of benzimidazole and triazole carbenes with ketenimines and their application in the construction of spiro-pyrroles

“…7 In addition to cycloaddition with heterocumulenes to afford cyclic products, N-heterocyclic carbenes are also known to form stable zwitterions in the nucleophilic addition to cumulenes and heterocumulenes, such as allenoates, 8 isothiocyanates, 9 isoselenocyanates, 10 carbon dioxide 11 and carbon disulfide. 12 In recent years, the ambident bis-dipoles derived from the addition of N-heterocyclic carbenes to aryl isothiocyanates have been developed into versatile synthons for the construction of novel spiro-and fused thiophene or pyrrole derivatives by our group. 13 Although reactions between nucleophilic carbenes and different heterocumulenes have been well documented, their reaction with ketenimines that are structurally similar to isocyanates and ketenes have been rarely reported.…”