Metal homoenolates are characterized by the juxtaposition of an organometallic species b to a carbonyl group. These bifunctional reagents require a delicate balance between stability and reactivity for applications in C À C bond formations. A particularly useful class of homoenolates is zinc homoenolates. It is not surprising that known zinc and related metal homoenolates are limited primarily to those bearing weakly electrophilic esters, amides, and nitriles. [1,2] In contrast, little is known about zinc homoenolates of ketones and aldehydes because of the known proclivity of metal homoenolates to cyclize into the corresponding cyclopropoxides. [3] An attractive synthesis of cyclopropanols by treatment of a,bepoxy ketones with CH 2 (ZnI) 2 indeed corroborates facile cyclization of zinc keto homoenolates to the corresponding cyclopropoxides.[4] Nonetheless, we hypothesized that subsequent transmetalation with a suitable metal could shift the otherwise unfavorable equilibrium to generate b-keto homoenolates for subsequent elaboration [Eq. (1); M = metal]. As part of research programs on synthetic applications of the Kulinkovich cyclopropanation, [5,6] we report herein the preparation and in situ S N 2' alkylation of mixed zinc/copper keto homoenolates.Treatment of cyclopropanol with diethylzinc should result in formation of the zinc alkoxide A and ethane (Scheme 1). A could be in equilibrium with the homoenolate B, where the former is expected to be strongly favored. In situ trapping of B by transmetalation could afford D for subsequent reactions.

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Despite the utility of imidazoles for a wide variety of chemical and biological applications as well as the growing research in imidazolium-based ionic liquids (ILs), synthetic studies and characterization data for N-functionalized imidazole derivatives with substituents present at the C(2) and/or C(4) and/or C(5) positions are generally unreported. Here, we modify our prior method for synthesizing monofunctionalized imidazoles and apply it to the production of a library of 30 di- and trifunctionalized alkylimidazoles using only commodity chemicals and avoiding anhydrous solvents or air/water-sensitive reagents. For all products, purities of >98% could be readily achieved, although yields were lower than in our prior work with imidazole, which may be due to mass transfer limitations and/or increased nucleophilicity of substituted imidazole products. Interestingly, we also observe that, when 4-methylimidazole or 2-ethyl-4-methylimidazole is used as a starting material, two regioisomers are inevitably formed. We employed electronic structural calculations to aid in identifying the chemical shifts and quantifying the relative presence of the regioisomers. In both series of compounds where regioisomers could be formed, the 4-methyl regioisomer was favored. Although the formation of similar regioisomers has been previously noted in the literature, it has perhaps not been fully considered in works related to imidazolium-based ILs.