a b s t r a c tThe reactions of organoaluminum reagents (trimethylaluminum, triethylaluminum, etc.) with aryl and alkyl acyl phosphonates, which lead to the formation of a-hydroxy phosphonates in moderate to good yields, are reported. This method provides easy access to secondary and tertiary a-hydroxy phosphonates depending on the reaction conditions. The reactions of triethylaluminum with a series of acyl phosphonates at 0 C gave the secondary a-hydroxy phosphonates, while at À100 C they afford the tertiary a-hydroxy phosphonates.