Hydrophosphorylation of alkenes with dialkyl phosphites catalyzed by Mn(III) under air

A facile method for the synthesis of organophosphonates from alkenes and dialkyl phosphites was developed by the use of Mn(II) under air. Thus, the reaction of 1-octene with diethyl phosphite in the presence of Mn(OAc)(2) (5 mol %) under air at 90 degreesC led to diethyl octylphosphonate (78%) and diethyl (2-hexyl)decylphosphonate (6%). Internal alkenes such as cis-2-octene gave a regioisomeric mixture of the corresponding hydrophosphorylation products in 84% yields.