Abstract: Two different alcohols, RIOH and R20H, are converted into an unsymmetrical phosphodiester,(R'O)(R20)-P (O) OH, without isolation of intermediates. Alternatively, the two alcohols are converted into a phosphotriester,(R'0)-(R20) P (0) OCH (CH3) COCH3, which is isolated and hydrolyzed to the phosphodiester with or without further purification. The procedures are made possible by the efficient imidazole catalysis of the ...