J. Kelly, S. Evans
Nov 1, 1986
Citations
0
Influential Citations
11
Citations
Journal
Journal of the American Chemical Society
Abstract
Diethoxytriphenylphosphorane (DTPP) selectively diphosphoranylates the vicinal diol functional group in 1,2,4-triols affording thermodynamically stable 2,2,2-triphenyl-1,3,2-dioxaphospholanes. When subjected to thermolysis conditions, these dioxaphospholanes dissociate to form transient betaines which subsequently collapse, via 3-exo-tet extrusion of triphenylphosphine oxide, to epoxides. The structures of the 2,2,2-triphenyl-1,3,2-dioxaphospholanes are readily assessed from /sup n/J/sub /sup 31/P-/sup 13/C/ (n = 2,3) coupling constants and /sup 31/P chemical shifts. Alkyl and aryl substituents attached to the dioxaphospholane ring also induce pronounced substituent shielding effects on the /sup 31/P resonance of the phospholanes. These effects are useful in corroborating the structural assignments of the dioxyphosphoranes.