Olefins and acetylenes with

TABLE 13. Annelation of olefins and acetylenes with tetrachlorothiophene 1,1-dioxide116... 

B. Reactions.—This year has seen the publication of a number of papers on the reactions of olefins and acetylenes with phosphorus pentachloride, to produce new phosphorus-carbon bonds. An investigation into the structural requirements of trisubstituted olefins (40) undergoing the above reaction has shown that both steric and electronic factors are important, e.g. an adduct forms with (40 X = CH3) but no reaction occurs for (40 X = Ph). Further examples of the reactions of unsaturated ethers include the formation and decomposition of adducts from a-methoxystyrene... 

For a decade or so [CoH(CN)5] was another acclaimed catalyst for the selective hydrogenation of dienes to monoenes [2] and due to the exclusive solubility of this cobalt complex in water the studies were made either in biphasic systems or in homogeneous aqueous solutions using water soluble substrates, such as salts of sorbic add (2,4-hexadienoic acid). In the late nineteen-sixties olefin-metal and alkyl-metal complexes were observed in hydrogenation and hydration reactions of olefins and acetylenes with simple Rii(III)- and Ru(II)-chloride salts in aqueous hydrochloric acid [3,4]. No significance, however, was attributed to the water-solubility of these catalysts, and a new impetus had to come to trigger research specifically into water soluble organometallic catalysts. 

Atkinson, J. G., D. E. Ayer, G. Btichi, and E. W. Robb Photochemical reactions XII. Addition reactions of olefins and acetylenes with benzo-nitrile. J. Amer. chem. Soc. 85, 2257 (1963). 

The interaction of unsaturated molecules, for example olefins and acetylenes, with transition metals is of paramount importance for a variety of chemical processes. Included among such processes are stereospecific polymerization of olefin monomers, the production of alcohols and aldehydes in the hydroformylation reaction, hydrogenation reactions, cyclo-propanation, isomerizations, hydrocyanation, and many other reactions. 

Of the aforementioned transition metal-catalyzed Grignard exchange reactions, the most standard method that has the broadest applications in organic synthesis is perhaps a titanium-catalyzed hydromagnesation of olefins and acetylenes with low molecular weight Grignard reagents. 

Other applications of titanium catalysts are hydromagnesation and carbomagnesation of unsaturated compounds, such as olefins and acetylenes with Grignard reagents. These are described in Chapter 3. 

Scheme 2.21 Hydrofluorination of olefins and acetylenes with 70% HF-pyridine and polyvinyl-pyridine hydrofluoride (PVPHF) [55a, 56, 61].

The first studies on the reaction of olefins and acetylenes with diborane met with little success. In the gas phase, olefins react sluggishly over long periods at elevated T to give mixtures . Acetylene gives polymeric organoboranes . However, in ether solvents, the addition is fast and quantitative at 0°C The catalytic effect of ethers is attributed to the formation of weak, reactive borane complexes ... 

The regioselectivity in hydroboration of functionalized olefins and acetylenes with borane is influenced by substituents located in the vinylic and allylic positions. For... 

The possibility of synthesizing alkyl and alkenyl silanes from olefins and acetylenes with silane, SiH, has been investigated by White and Rochow (128). With ethylene various ethyl derivatives of silane and disilane were obtained under conditions suggestive of a free-radical mechanism ... 

It is interesting that direct conversion of methane to styrene can be carried out over the mixed catalyst La203 + M0O3/H-ZSM-5 [82], Perspective homologation of olefins and acetylene with methane on transition metals has been demonstrated [83],... 

Sharpless, K.B., and T.R. Verhoeven, Metal-Catalyzed Highly Selective Oxygenations of Olefins and Acetylenes with t-BuOOH. Practical Considerations and Mechanisms,... 

Cooligomerization (hetero-oligomerization) of olefins and acetylenes with butadiene in the presence of nickel complexes prevents the formation of butadiene trimers. During hetero-oligomerization chain and cyclic compounds may be formed see equations (13.87) and (13.88). Dodeca-2,6,10-triene-l,12-diylnickel reacts with allene to give various products. Reaction (13.89) is an example. 

Cobalt, nickel, iron, ruthenium, and rhodium carbonyls as well as palladium complexes are catalysts for hydrocarboxylation reactions and therefore reactions of olefins and acetylenes with CO and water, and also other carbonylation reactions. Analogously to hydroformylation reactions, better catalytic properties are shown by metal hydrido carbonyls having strong acidic properties. As in hydroformylation reactions, phosphine-carbonyl complexes of these metals are particularly active. Solvents for such reactions are alcohols, ketones, esters, pyridine, and acidic aqueous solutions. Stoichiometric carbonylation reaction by means of [Ni(CO)4] proceeds at atmospheric pressure at 308-353 K. In the presence of catalytic amounts of nickel carbonyl, this reaction is carried out at 390-490 K and 3 MPa. In the case of carbonylation which utilizes catalytic amounts of cobalt carbonyl, higher temperatures (up to 530 K) and higher pressures (3-90 MPa) are applied. Alkoxylcarbonylation reactions generally proceed under more drastic conditions than corresponding hydrocarboxylation reactions. 

Evidence for such a scheme has been presented for hydrogenations conducted with simple Ru(II) salts, HCo(CO)4, [HCo(CN)s] , or [Pt(SnCl3)s] as catalysts 188-191). These homogeneous catalysts function best with terminal olefins and acetylenes. With dienes as substrates, the anionic catalysts selectively hydrogenate only one of the two double bonds. These complexes also catalyze olefin isomerization and, in the case of nonconjugated dienes, isomerization to a conjugated diene may precede hydrogenation. 

The formylation reaction is a mixed success. While the coupling of aryl, vinyl, or allyl halides (triflates) is effective, quite often the conditions are harsh. The formylation of alkyl halides or hydroformylation olefins and acetylenes with palladium is not the method of choice for preparing the corresponding aldehydes. 

Cycloaddition.— Reactions of electrophilic olefins and acetylenes with tricarbonyl-iron complexes of cycloheptatriene and cyclo-octatetraene lead to 1,3-exo-products. Troponetricarbonyliron and tcne, however, have now been found to give complex (20) which results from previously unobserved 1,5-exo-cycloaddition. A dipolar intermediate (21) resulting from initial attack by the electrophile on the hydrocarbon... 

Features in the polymerization of dienes, olefins, and acetylenes with rare earth Coordination catalysts... 

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