Stereochemistry of Reactive Intermediates in Organophosphorous Chemistry

A new synthetic route to produce a phosphonyl radical in the ground state has been devised. The radical is capable of maintaining its structural integrity and geometry. In polar aprotic solvents the radical can equilibrate depending upon reaction conditions. Our results are significant for they show that the homolytic cleavage of a phosphorous oxygen bond could by changing the configuration at phosphorous, influence the biological properties of naturally occurring compounds. The stereochemistry of 2-substituted-5-ch1oromethyl-5methy1-2-oxo-1,3,2-dioxaphosphorinans can be established by proton NMR spectroscopy. Methanolysis of 2-hydrazinophosphorinans has been investigated. Cis and trans 2-hydrazinophosphorinans undergo acid catalyzed methanolysis to give products of both retention and inversion. The product ratio is dependent upon the strength of the acid used. Under strong acid conditions, the product ratio is nearly identical for both the cis and trans isomers. Stereochemical evidence for the participation of a phosphacylium ion-like intermediate is presented