Synthetic and structural studies of phosphonic amides and esters

Abstract

The research contained herein is of twofold nature. Firstly, we aimed to obtain a mechanistic understanding of the thermal fragmentation reaction of B-acyloxyphosphonates, and in the process we secondly aimed to develop synthetic methodology for phosphonic diamides. We showed that the fragmentation of B-acyloxyphosphonates proceeds with metaphosphate extrusion preceded by a novel type of molecular rearrangement. It is, to our knowledge, the first example in which alkyl migration from the oxygen of the phosphorus ester function to another centre (in this case carbonyl oxygen of the substrate) has to take place in order to allow metaphosphate extrusion. We succeeded m developing synthetic methodology by which alkylphosphonic and B-hydroxyalkylphosphonic diamides can be obtained in good yields using simple procedures. Reaction of the anion of HP(O)(NEt2) 2 with either alkyl halides or epoxides was used to obtain these compounds. In making alkyl- and 8-hydroxyalkylphosphonic diamides more easily accessible than before, more of the chemistry of these compounds can be studied.