Reaction of Stannyl Esters of Phosphorus Acids with Sulfonic Acids Chlorides and Carboxylic Acids Anhydrides. A Novel Synthesis of Phosphoric-Sulfonic and Phosphoric-Carboxylic Anhydrides

Mixed anhydrides of phosphorus sulfonic acids RR'P(O)OSOzR" 1 are of interest in the biological transfer of sulfates'. In the chemical synthesis of oligonucleotides, phosphoric sulfonic anhydrides 1 (R', R = nucleoside) are postulated as important and reactive intermediatesw-s-. Anhydrides 1 were also suggested as intermediates in biooxidation of thiolophosphates'. Structural analogues of anhydride 1, derived from phosphorus monothioacids, were successfully used as models for studying the mechanism and stereochemistry of nucleophilic displacement reactions at the tetra-coordinate phosphorus centre5,6,7. Satisfactory syntheses of phosphorus-sulfonic anhydrides 1 have been reported only recently's". From the point of view of the nucleotide and medicinal chemistry it has become interesting to explore the scope of previously described methods for the preparation of 1 and to discover new routes of potential applicability to the chemistry of reactive phosphorus compounds of biological interest!", Our recent approach" to the synthesis of mixed anhydrides 1 was based on the phosphorus silyl and stannyl esters (reactions 1 and 2).