The first examples of enantiomerically pure diphosphane dioxides (R-P,R-P)- and (S-P,S-P)-1,2-di-tert-butyl-1,2-diphenyldiphosphane 1,2-dioxides, and (R-P)- and (S-P)-1-tert-butyl-1,2,2-triphenyldiphosphane 1,2-dioxides

Whereas oxidative dimerization of each of the lithiated reagents (R-p)- and (S-p)-tert-butylphenylphosphane oxides 1 Li and 2 Li by means of oxygen in THF at low temperature led cleanly to meso-1,2-di-tert-butyl-1,2-diphenyldiphosphane dioxide (3), the respective nucleophilic substitution reactions of 1 Li and 2 Li with the (R-p)- and (S-p)-tert-butylphenylphosphinic bromides (4 and 6) in THF under argon led to the corresponding (S-p,S-p)- and (R-p,R-p)-1,2-di-tert-butyl-1,2-diphenyldiphosphane dioxides (5 and 7) in good yields, together with the meso-diphosphane dioxide 3. The structures of 3 and 5 were established by X-ray crystallography. Similarly, the reaction of lithiated (R-p)-phosphane oxide 1 Li with diphenylphosphinic bromide (8) or of achiral lithiated diphenylphosphane oxide 10 Li with (R-p)-tert-butylphenylphosphinic bromide (4) provided (S-p)-tert-butyltriphenyldiphosphane dioxide (9).