Solid‐state conformation of the 1,3,2‐oxazaphospholane ring in 2‐dialkylamino‐3,4‐dimethyl‐5‐phenyl‐1,3,2‐oxazaphospholane sulfides

Dialkylamino‐3,4‐dimethyl‐5‐phenyl‐1,3,2‐oxazaphospholane sulfides (where the alkyl is an isopropyl, ethyl or methyl group) was obtained by sulfurization of the respective phospholanes. The structures of these compounds were determined by X‐ray crystal structure analysis. Five‐membered rings exist in the envelope conformation in the crystalline state. The planar part of the 1,3,2‐oxazaphospholane rings undergoes twisting with the enlargement of a substituent. The environment of the P atom has the geometry of a distorted tetrahedron. © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:146–150, 2001