Investigation of Counterion Effects in an Organocatalyzed Iodolactonization and Discovery of an Organocatalyzed Iodolactonization to Give 7-Membered Lactones

Abstract

Iodolactonization is a venerable chemical reaction with considerable utility in the synthesis of organic compounds. More recently, enantioselective methods reliant upon organocatalysts have been developed. This work details the investigation into a previously developed organocatalyst-mediated asymmetric iodolactonization towards δ-iodolactones via modulation of the catalyst salt counterion. It further details the discovery of an enantioselective iodolactonization towards the much more challenging ε-iodolactones reliant upon an organocatalyst and a new oxidant system, along with subsequent reaction optimization, limited mechanistic investigation, and preliminary substrate scope.