Halogen-sodium exchange enables efficient access to organosodium compounds

With sodium being the most abundant alkali metal on Earth, organosodium compounds are an attractive choice for sustainable chemical synthesis. However, organosodium compounds are rarely used-and are overshadowed by organolithium compounds-because of a lack of convenient and efficient preparation methods. Here we report a halogen-sodium exchange method to prepare a large variety of (hetero)aryl- and alkenylsodium compounds including tri- and tetrasodioarenes, many of them previously inaccessible by other methods. The key discovery is the use of a primary and bulky alkylsodium lacking beta-hydrogens, which retards undesired reactions, such as Wurtz-Fittig coupling and beta-hydrogen elimination, and enables efficient halogen-sodium exchange. The alkylsodium is readily prepared in situ from neopentyl chloride and an easy-to-handle sodium dispersion. We believe that the efficiency, generality, and convenience of the present method will contribute to the widespread use of organosodium in organic synthesis, ultimately contributing to the development of sustainable organic synthesis by rivalling the currently dominant organolithium reagents. Halogen-sodium exchange reactions with neopentyl sodium provides access to a range of aryl and alkenyl organosodium compounds in situ, as an alternative to organolithium reagents.

Automated summary

The halogen-sodium exchange method allows for the preparation of a variety of aryl and alkenylsodium compounds, including previously inaccessible products. The use of a unique alkylsodium compound with no beta-hydrogens has been shown to efficiently suppress undesired reactions and make the method convenient and widely applicable.