Rhodium-catalyzed enantioselective transfer hydrogenation of α-substituted β-ketophosphonates via dynamic kinetic resolution

A rhodium-catalyzed asymmetric transfer hydrogenation (ATH) of α-chloro β-ketophosphonates via dynamic kinetic resolution (DKR) has been developed. A wide range of syn α-chloro β-hydroxyphosphonates were efficiently synthesized with high yields and excellent enantio- and diastereoselectivities (up to 99% ee and > 99 : 1 dr) under mild reaction conditions. A gram-scale experiment was conducted successfully, which offers a straightforward approach to a key intermediate of fosfomycin.