Stability, reactivity, solution, and solid-state structure of halomethylzinc alkoxides

In this paper, we report our findings regarding the development of a Lewis acid-catalyzed cyclopropanation of allylic alcohols with bis(iodomethyl) zinc. Iodomethylzinc alkoxides can be formed by treatment of an alcohol with bis(iodomethyl)zinc. These species are not prone to undergo cyclopropanation at low temperature but the addition of a Lewis acid in catalytic amounts induces the cyclopropanation reaction. Using this procedure, we demonstrated that the Lewis acid-catalyzed pathway significantly overwhelms the uncatalyzed one. This paper describes fundamental issues regarding the preparation and stability of halomethyl zinc alkoxides in solution as well as their aggregation state in solution and solid-state structures. Furthermore, the competition reaction between the inter- vs intramolecular cyclopropanation will be studied. Finally, we will discuss the possible activation pathways to explain the Lewis acid activation of halomethylzinc alkoxides. These findings provided new insights on the reactivity of ROZnCH2I and established the groundwork for the elaboration of an enantioselective version of the reaction.