Six-membered cyclic phosphate-phosphonates: Synthesis and stereochemistry of cis/trans-2-phosphorylbenzyloxy-4-aryl-5,5-dimethyl-1,3,2λ ⁵-dioxaphosphorinane-2-thiones (selones)

A study on the synthesis and stereochemistry of the novel six-membered cyclic phosphate-phosphonates, cis/trans-2-phosphorylbenzyloxy-4-aryl-5,5-dimethyl-1,3,2λ ⁵-dioxaphosphorinane-2-thiones (selones) 7a-f has been carried out. The title compounds were obtained in good overall yields by a one-pot procedure using tris(diethylamino)phosphine activated by iodine as the phosphorylating and ring-closing reagent. Their geometric stereoisomers were isolated and characterized. A cis-configuration and a preferred chair conformation of one isomer of 7b have been established by X-ray diffraction analysis. This study also gives a good explanation for the correlation between the configurational assignments and the chemical shifts of C₄-H and ³¹P, which shows some difference from previously reported results.