EVALUATION OF THE P-IV=S REDUCTION-COMPLEXATION BY NICKELOCENE AS A SYNTHETIC TOOL IN ORGANOPHOSPHORUS CHEMISTRY - TOWARDS THE SYNTHESIS OF FUNCTIONAL PHOSPHINES WITH AN OPTICALLY-ACTIVE PHOSPHORUS CENTER

Metalation of PhP(S)Me2 by BuLi followed by reaction with carbonyl derivatives afforded functional and chiral phosphine sulfides of general formula PhP(S)(Me)CH2Z with Z Ph2C(OH), PhC(O), HC(O), COOEt; with Ph2CO [Z Ph2C(OH)] a bifunctional compound PhP(S)(CH2Z)2 was also obtained. These sulfides were reduced to the corresponding phosphines L through their CpNi(I)L complexes by treatment with nickelocene and allyl iodide followed by decomplexation with P(OMe)3. The synthesis of the phosphinoacetaldehyde is especially noteworthy. Use of an optically active phosphine sulfide showed that this reduction-complexation-decomplexation procedure proceeded with full retention of configuration at phosphorus. Thus, it is possible to synthesize functional phosphines with an optically active phosphorus centre. The synthesis of two optically active nickelocenes [R* C5H4]2Ni is described. When treated with a phosphine sulfide LS they yielded the corresponding optically active [R*C5H4]Ni(I)L complexes. When L was chiral, attempted separation of the diastereoisomeric complexes failed. © 1979.