Organosulfur compounds. 14. Dimethyl selenoxide oxidation of trivalent phosphorus compounds, thio- and selenophosphoryl compounds, and thiocarbonyl compounds. Stereochemical studies and selective modification of the thiocarbonyl-containing nucleic acid components

Synthesis of a Δ4‐1,4,2λ5‐Selenazaphospholine, the First Selenophosphorane

“…The product turned out to be sensitive to hydrolysis and thermolabile. The spectroscopic dataU5] are consistent with the structure of a A4-I ,4,2h5-selenazaphospholine (3). The 'JpH coupling of 1.5Hz demonstrates the presence of the structural unit P-SeCNC-H.…”

Stereogenic Phosphorus

“…A further intriguing reaction of the quinquevalent tetracoordinated phosphorus is the exchange of phosphoryl oxygen and thiophosphoryl sulfur at stereogenic phosphorus. The conversion can be made to proceed stereospecifically in each direction through the use of the appropriate reagents, phosphorus pentasulfide or boron trisulfide for the generation of thiophosphoryl compounds from phosphoryl species, and, among others, ozone (retention) or trifluoroacetic anhydride (inversion) [25,44,[137][138][139][140][141][142][143][144][145][146][147][148][149][150][151][152] for the generation of phosphoryl compounds from thiophosphoryl and selenophosphoryl species, as shown in Scheme (15). These reactions proceed through pentacoordinated phosphorus intermediates, species which themselves are quite interesting and the topic of the following section of this treatment.…”

1-Phosphabicyclo[2.2.1]heptane

“…Die Diederwinkel EP, P, C-2, C-3 bzw. EP, P, C-6, C-5 liegen bei 160°, der Diederwinkel EP, P C-7, C-4 bei 180°und liefern damit erwartungsgemäß [18Ϫ20] einen kleinen und [29], gelöst in CHCl 3 , oxidiert [30]. Nach Ersatz von CHCl 3 durch Benzol wird durch Erhitzen am Rückfluß die Umwandlung des roten Selens vervollständigt.…”