Crystal Structure of cis-2-〔(P,P-Diethoxy)phosphono(m-nitro)benzyloxy〕-4-Phenyl-5,5-Dimethyl-1,3,2-Dioxaphosphorinane 2-Sulfide

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Crystal Structure of cis 2 (P,P Diethoxy) phosphono( m nitro)benzyloxy 4 Phenyl 5,5 Dimethyl 1,3,2 Dioxaphosphorinane 2 Sulfide ①

The crystal structure of the title compound cis 2 (P, P Diethoxy)phosphono( m nitro)benzyloxy 4 Phenyl 5,5 Dimethyl 1,3,2 Dioxaphosphorinane 2 Sulfide, C 22 H 29 NO 8P 2S, was determined by single crystal X ray diffraction. It crystallizes in the monoclinic system, space group P2 1/c, with M r=529.49, a=9.888(2), b=20.831(4), c=12.797(3) , β=94.42(3)°, V=2628(1)  3, Z=4, D x =1.338 g/cm 3 , λ=0.71073 , μ =0.2796 mm 1 and F(000) =556. The structure was solved by direct methods. The final R factor is 0.052 and R w is 0.057 for 1793 unique observed reflections I≥3σ(I) . A cis configuration and a preferred chair conformation for the molecule have been established by X ray diffraction analysis. The results presented also give a good explanation to the correlation between the configurational assignments and the regularity in the chemical shifts of C 4-H and 31 P NMR.