CONFORMATION OF OXATHIAPHOSPHOLANE AND DITHIAPHOSPHOLANE RINGS IN THESOLID-STATE

In this paper, the geometry and conformation of oxathiaphospholane and dithiaphospholane rings in the solid state are described on the basis of our recent work and compared with literature data. For oxathiaphos pholane rings in the solid state, both envelope and half-chair conform ations, differently distorted, are observed. In oxathiaphospholane rin gs with the envelope conformation, the endocyclic carbon atom next to the ring oxygen atom is in the flap position. For dithiaphospholane co mpounds, the heterocyclic rings prefer a half-chair conformation or th e conformation intermediate between half-chair and envelope forms; the envelope conformation is observed only in one case.