The structure of the imidazolium salt of 2-hydroxy-1,3,2-dioxaphospholane 2-sulphide

Stereoselective PCO/POC-Rearrangement of P–C-Cage Phosphorane in the Reaction of 4,5-Dimethyl-2-(2-oxo-1,2-diphenyl)ethoxy-1,3,2-dioxaphospholane with Hexafluoroacetone

“…Their unusual skew to the same side arises because deviation of the C 7 atom from the O 1 P 2 O 3 C 4 plane is partially compensated by deviation of the C 5 atom from this plane in the same direction. Dimethyl dioxaphospholane cycle with different coordination of the phosphorus atom (III, IV, VI) usually possesses a flattened envelope conformation with a small deviation of either phosphorus or carbon atom from the ring plane. ,− …”

The imidazole complex of 2-hydroxy-4,4,5,5-tetramethyl-1,3,2-dioxaphospholane 2-sulphide

“…We report here the X-ray analysis of the imidazole complex (see Introduction) of 2-hydroxy-4,4,5,5-tetramethyl-1,3,2-dioxaphospholane 2-sulphide (Ig). The five-membered dioxaphospholane ring has been found to be non-planar in all previous investigations (Steitz & Lipscomb, 1965;Chiu & Lipscomb, 1969;Newton, Cox & Bertrand, 1966;Wieczorek, Karolak- Golifiski, Bartczak, Mikotajczyk & Witczak, 1976;Saenger & Eckstein, 1970;Mikotajczyk, Witczak, Wieczorek, Bokiy & Struchkov, 1976;Andrianov, Kalinin & Struchkov, 1977;Newton & Campbell, 1974;Bentrude & Hart-Wan Tan, 1976). The dioxaphospholane ring in (Ig) displays a half-chair conformation [distances from the best least-squares plane: P 0.017, 0(2) 0.121, C(2) -0.214, C(1) 0.230, 0(3) -0-153 A] with C(1) displaced more than C(2) from the plane defined by P, 0(2) and 0(3).…”