Cyclic organophosphorus compounds. Part 20. Structural correlations in the 2-amino-4-methyl-1,3,2-dioxaphosphinane series. X-Ray molecular structure of cis-2-t-butylamino-4-methyl-1,3,2-dioxaphosphinane 2-oxide

Abstract

The oxidation of cis-2-t-butylamino-4-methyl-1,3,2-dioxaphosphinane 2-selenide with hydrogen peroxide yields cis-2-t-butylamino-4-methyl-1,3,2-dioxaphosphinane 2-oxide. The oxide has been shown, by X-ray analysis, to exist in the chair form with the methyl and t-butylamino groups orientated equatorially, and the structure has been refined to R= 0.097. with a= 11.304(1), b= 9.702(1), c= 11.386(1)Å and β= 116.16(2)°. Predictions regarding the stereoretentive course of this oxidation procedure made elsewhere on the basis of n.m.r. data are thus confirmed. Further ¹³P chemical shift and ¹J(³¹P,⁷⁷Se) data now suggest that the correlation can be extended to include the 2-anilino and 2-benzylamino compounds.