Triphenylphosphine, aliphatic halide

Carbonyl compounds are capable of undergoing another completely different sort of reaction, in which the carbonyl oxygen is replaced, not by a heteroatom as we saw above, but by an sp carbon atom. When triphenylphosphine is treated with a secondary aliphatic halide, a normal substitution reaction occurs, resulting in the replacement of the halide by the phosphorus compound. This phosphonium salt adduct may then be treated with a very strong base, such as phenyllithium, to produce an ylid. An ylid is a compound in which there is a positive charge adjacent to a negative charge. Write down this reaction sequence. 

The salt [CpFe(CO)3](CFjS03) is stable in air, but it changes from yellow to brown slowly if stored in a desiccator over a long period of time. It is soluble in acetone and acetonitrile but only slightly soluble in dichloromethane. When treated with triphenylphosphine in acetone, [CpFe(CO)3] forms [CpFe(CO)2 (PPhj)]. The cation reacts with halide ions to form the neutral complexes CpFe(CO)2X (X = Cl, Br, and I). Treatment of [CpFe(CO)3] with aliphatic... 

The Sonogashira reaction allows for the direct cross-coupling of terminal alkynes with aryl halides under mild conditions through use of catalytic bis(triphenylphosphine)-palladium dichloride and Cul as the co-catalyst in the presence of an aliphatic amine. The formation of diphenylacetylene exemplifies the original Sonogashira reaction conditions ... 

Wilkinson s catalyst and chlorocarbonylbis(triphenylphosphine)rhodium [or iridium] can catalyze the thermal decarbonylation of aromatic acid halides to aryl halides. An intermediate Rh(III) hydride is involved in the reaction (Suggs, 1978). For aliphatic acid halides, subsequent elimination of HX frequently occurs from the generated alkyl halide (Ohno and Tsuji 1968 Blum et al., 1%7, 1971 Strohmeier and Pfohler, 1976). 

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