Electrochemical enantioselective α-chlorination of aldehydes

Organic electrochemistry offers several advantages over traditional chemical oxidation methods, such as the possibility to avoid the use of stoichiometric oxidizing agents and toxic or hazardous reagents1. Typically, organic electrochemistry transformations require milder reaction conditions compared to traditional oxidation approaches, since electrons are used as traceless redox equivalents to perform the process without the need for additional redox reagents2. In this context, we focused our attention on the development of a stereoselective synthesis of α-chloroaldehydes by organo electrochemical approach, taking advantage of linchpin catalysis. α-chloroaldehydes have been synthetized with high level of enantioselectivity starting from unactivated aldehydes using a chiral amine as organocatalysts in the presence of a cost-effective and environmentally friendly Cl- source. These α-chloroaldehydes were then rapidly converted (in-situ) into several significant building blocks such as aziridines, epoxides, and amino acids. Desired products were obtained in good yields (from 75 % to 95 %) and up to 97% ee (determined on the corresponding chlorohydrin derivates) (Figure 1). The identical methodology approach was also explored under flow conditions to enhance productivity and space-time yields for gram-scale production.