Nickel carbonyl phosphine derivatives

The ability of nickel complexes, e.g., nickel carbonyl and its phosphine derivatives, to catalyze polymerization and other reactions of olefins and acetylenes has been studied extensively (46, 53), particularly by Reppe. 

The general mechanistic picture presented above applies to a number of synthetically useful systems including the first to be discovered, in which trimerization of acetylene to benzene, and propargyl alcohol to a 1 1 mixture of 1,2,4- and 1,3,5-trisubstituted benzene derivatives was catalyzed by (Ph3P)2Ni(CO)2. Phosphine nickel carbonyls are usually much more highly regioselective for 1,2,4-... 

Meriwether et al. (70) also proposed a mechanism for the aromatization reaction, shown in Fig. 5. According to these workers formation of benzene derivatives would necessitate migration of hydrogen atoms. Since some disubstituted alkynes may also be cyclotrimerized with phosphine-nickel carbonyl catalysts, this mechanism is less probable. 

Treatment of propiolic esters with catalysts of the type Ni(PX3)4 affords small amounts of tetrasubstituted cyclooctatetraenes in addition to benzene derivatives. This is the only other reported instance of cyclotetramerization of an alkyne using a Ni(0) catalyst 86). The synthesis of heptatrienenitrile was discovered in 1952 by Cairns et al. 87). These authors treated acetylene with acrylonitrile in the presence of phosphine-substituted nickel carbonyls. Under these conditions the reaction requires an induction period during which bis(acrylonitrile)-nickel and/or its phosphine adducts are formed. Bis(acrylonitrile)-nickel in the presence of triphenylphosphine is now known to be immediately reactive under similar conditions 42). Formation of (XL) must involve a hydrogen shift, and may proceed according to Eq. (22)... 

Acrylonitrile can be replaced by acrylic esters in these processes (S6). It is difficult to explain why these reactions afford only linear condensation products and not aromatic oi cycloolefinic compounds. Bis(acrylonitrile)-nickel also reacts with 2-butyne (78) and hexafluorobutyne (88), forming the corresponding benzene derivative and linear oligomers and polymers, respectively. Since phosphine-modified nickel carbonyls usually fail to... 

Wilkinson (9) isolated the tetrakis(trihalogenophosphine)nickel compounds Ni(PX3)4 (X= F, Cl, Br), and Behrens (10) isolated the triphenylphosphine complex Ni[P(C6H5)3]4 via [Ni(CN)4]4. With iron pentacarbonyl, isonitriles and phosphines yield (11) mono- and disubstituted derivatives, Fe(CO)4L and Fe(CO)3L2, respectively, the latter being the well-known cyclization catalyst of Reppe (7). With the same ligands, carbonyls of the chromium group afforded pentacarbonyl derivatives M(CO)5L. However,... 

Thiocarbonyl derivatives of 1,3-dioxolanes and 1,3-oxathiolanes are readily isomerized to the 2-carbonyl compounds as shown in Scheme 20. Alkylation of the sulfur atom with alkyl halides usually leads to ring-opened products (Scheme 21) (69JOC3011). Most of the other chemistry of the sulfur derivatives has focused on desulfurization and subsequent generation of alkenes. The reaction is shown in equation (20) and proceeds with cis elimination via carbene intermediate (see Section 4.30.2.2.5) and is usually carried out with a phosphine (73JA7161) or a zero-valent nickel complex (73TL2667). 

By Direct Replacement on Tetracarbonyinickel. This was the first way by which nickel(O) carbonyl derivatives, different from Ni(CO)4, were obtained with tertiary phosphines, arsines, stibines 160) j and bismutines 17) j and with triarylphosphites 131) and arsenites 17). 

However, it was not generally possible to obtain trisubstituted compounds from phosphines (except for trimethylphosphine 19)), while the phosphites give the trisubstituted derivatives 131) easily. Later Bigorgne 19) described all the possible substitution derivatives of carbonyl nickel with trimethylphosphite and triethylphosphite. 

The olefin complexes of iron, nickel, rhodium, and iridium described in this chapter have found broad application in the synthesis of phosphine, phosphite, and carbonyl derivatives of these metals. In Chapter Two, the synthesis of another labile olefin complex, (ethylene)bis(tricyclohexylphosphine)nickel, is described as an initial step in synthesis of a complex of dinitrogen. 

The catalytic hydrocarbonylation and hydrocarboxylation of olefins, alkynes, and other TT-bonded compounds are reactions of important industrial potential.Various transition metal complexes, such as palladium, rhodium, ruthenium, or nickel complexes, have widely been used in combination with phosphines and other types of ligands as catalysts in most carbonylation reactions. The reactions of alkenes, alkynes, and other related substrates with carbon monoxide in the presence of group VIII metals and a source of proton affords various carboxylic acids or carboxylic acid derivatives.f f f f f While many metals have successfully been employed as catalysts in these reactions, they often lead to mixtures of products under drastic experimental conditions.f i f f f In the last twenty years, palladium complexes are the most frequently and successfully used catalysts for regio-, stereo-, and enantioselective hydrocarbonylation and hydrocarboxylation reactions.f ... 

Similar to the results discussed for the silylcarbocyclizations of carbon-carbon multiple bonds, reductive cyclizations in the presence of carbonyl compounds are readily achieved. Crowe has developed a titanium-catalyzed procedure for the intramolecular reductive coupling of i5, -unsaturated carbonyl compounds in the presence of triethoxysilane (eq 18).The electronic advantage of triethoxysilane is demonstrated by the lack of reductive coupling in the presence of less reactive silanes, such as triethylsilane and diphenylsilane. With this method, Mori has utilized nickel(O) catalysts to generate five- and six-membered carbocycles and pyrrolidine derivatives. Furthermore, coordination of a chiral phosphine ligand to the nickel catalyst renders the reaction moderately enantioselective. ... 

---