Efficient Access to α-Substituted β-Keto Phosphonates via NHC-Catalyzed Dehaloacylation of α-Bromo Phosphonates

Abstract

β-Keto phosphonates are important scaffolds in bioactive molecules and synthetic intermediates, yet general methods for accessing α-substituted variants are scarce. Inspired by NHC-catalyzed radical acylation, we herein report an NHCcatalyzed dehaloacylation of α-bromo phosphonates with aldehydes. This redox-neutral catalysis enables the efficient synthesis of diverse α-substituted β-keto phosphonates under mild conditions with broad substrate scope and excellent functional group tolerance. The practical synthetic utility of this method is demonstrated through the modification of complex molecules, gram-scale synthesis, and further derivatization of the products into bioactive derivatives. This strategy overcomes a key limitation of previous approaches, providing a general and practical route to α-substituted β-keto phosphonates.