Darstellung von verbindungen MIT PP — und PPP — gerüsten

Recently, the importance of organophosphorus compounds in organic chemistry has increased. Diphosphines are an attractive source of phosphorus containing two phosphorus groups, which can theoretically be introduced into a carbon framework with high atom economy. There are several diphosphine derivatives, which are closely related to diphosphines, but their reactivities are completely different. In this Minireview, we describe various phosphination reactions with diphosphines and their derivatives under radical conditions.

Reactions of the hydrogen-bridged chelates cis-(CO)₄M(PPh₂O-)₂H⁻ (M  Cr, Mo, W) with Cl₂PPh yield complexes of the type cis-(CO)₄$\text{M(-P}$Ph₂-P(O)Ph-O-PPh₂) containing five-membered chelate rings. X-ray structural determination of the Mo complex confirmed the formation of the heterocycle.

Crystal data: space group C2/c; a 16.477(3), b 19.845(3), c 20.512(4) Å; β 106.61(2)°; Z = 8, D_calc 1.421 Mg m⁻³. The final residual is 0.027 for 4737 observed reflections. The five-membered chelate ring is nonplanar with the phosphoryl P 0.888(2) Å out of an approximate plane containing the other four atoms. For the tungsten analogue, ³¹P NMR data are consistent with the initial formation of a six-membered heterocyclic intermediate: cis-(CO)₄W(PPh₂-O)₂PPh, which tautomerizes readily to give the final product. Six-membered chelate rings containing the (PPh₂O)₂PPh ligand can be assembled by the reaction of cis-(CO)₄Mo(PPh₂Cl)₂ with (CO)₅M-PPhO₂H⁻ (M = Cr, Mo). Complexes of the type cis-(CO)₄Mo(PPh₂O-)₂PPh-M(CO)₅ (M = Cr, Mo) were isolated. Reaction of Cl₂PPh with two equivalents of (CO)₅Mo-PPh₂O⁻ yields PhP(-OPPh₂-Mo(CO)₅)₂. The above complexes represent coordination-stabilized PhP(-OPPh₂)₂ and (Ph₂P-)-

The (1,2) ambident nucleophilic anion diisopropylphosphite (RO)₂PO⁻ (R = Me₂CH) reacts with Ph_3—nPC1_n (n = 1,2) to yield PP bonded derivatives Ph_3—nP[P(O)(OR)₂]_n. The (1,3) ambident nucleophilic anions diisopropyl- phosphorothioate (RO)₂POS⁻, and diisopropylphosphorodithioate (RO)₂PS₂⁻ react with Ph_3–nPCl_n (n = 1,2) to yield Ph_3–nP[XP(Y)(OR)₂₂n (X = O, Y = S; and X = Y = S, respectively): the analogous diisopropylphosphoroselenoate (RO)₂POSe⁻ reacts with Ph₂PCl to give Ph₂P[OP(Se)(OR)₂], but PhP[OP(Se)- (OR)₂]₂ was too unstable to be characterised. Assignments of constitution are made, based on ³¹P NMR data: the thermodynamics of isomerisation are discussed.