Hydrocarbons, hydrocarbon isonitriles

A60. J. P. Candlin, K. A. Taylor, and D. T. Thompson, "Reactions of Transition-Metal Complexes. Elsevier, Amsterdam, 1968. A review of types of reactions of metal complexes (e.g., substitution, combination, redox) reactions with various reagents (e.g., hydrocarbons, halides, carbon monoxide, and isonitrile) and preparation of new stabilised organic systems (e.g., metallocenes, carbenes). Intended for research workers, consequently written at a fairly high level, with emphasis on organometallics. A61. H. J. Keller, NMR-Untersuchungen an Komplexverbindungen. Springer, Berlin, 1970. Expansion of review article 37.1. 

In the following sections, we will review the marine isonitriles by skeletal types. This permits comparison of their differences and may suggest biogenetic clues. Skeletal frameworks are generally revealed by reducing the isonitrile with lithium/ethylamine to the corresponding hydrocarbon. Where trivial names have been assigned for skeletal types and for compounds, we shall use these as reported in the literature. In some cases, when structures related to previously mentioned compounds are discussed, formula numbers will be employed. 

Several examples of the monocyclic isothiocyano sesquiterpenoids having the bisabolane (83) skeleton are known. Along with the hydrocarbon theonellin (84), isothiocyanate 86 and formamide 87 were obtained from the Okinawan sponge Theonella cf. swinhoei. It seems remarkable, but not unusual, that not only was the amide the major constituent, but the isonitrile 85 was the missing member of the triad [57], Relative stereostructures were indicated by NMR analysis of theonellin formamide (87) and its transformation products. 

Evidence forcoball(l) was first obtained from the electrolytic reduclion of cyano-compounds and some of the reduced species have been isolated. There arc also many cohaltfl) coordination compounds of Ihe organomelallic class carbonyl, isonitriles, and unsaturated hydrocarbon derivatives. The oxidation state cobalt(O) may be represented in the eyano-Lompound which has been formulated as Ks[Cu (CN)b. It has been prepared as an air-sensitive brown-violet compound by reducing a liquid ammonia solution of Kj Co(CN)f,l with an excess of K tnctal. The only other known coball(O) species arc organomelallic compounds. 

Ligand-exchange reactions of complexes having 7c-bonded hydrocarbon ligands are employed to prepare isonitrile complexes. Among these, 1,5-cyclooctadiene (COD) is... 

Hydrolysis yields final reduction products Reaction mixtures containing Mo salts and sulfur ligands, in aqueous base, with NaBH as the reducing agent, when treated with nitriles, isonitriles or [CN] react to produce hydrocarbons (CH, CjHj, etc.) in reactions of undetermined stoichiometry ... 

Table 4 Metal-Ammonia Reduction of Isonitriles to Hydrocarbons ...

The Bu3SnH decyanation of isonitriles (Scheme 16) was first reported by Saegusa, and was developed as a general, mild method for reductive deamination by Barton and coworkers who initially showed that a variety of isonitriles, isothiocyanates and isoselenocyanates reacted with Bu3SnH under the usual free radical conditions (reflux in benzene, toluene or xylene with catalytic AIBN) to give good yields of the corresponding hydrocarbon. In concert with the normal order of radical stability, primary... 

The product ethylene is formed in a stoichiometric yield with the nitrile and isonitrile, and for methylallenimine, (C2H4) = 0.25 and deactivating mechanism is also operative. The overall mode of decomposition bears a close resemblance to that of the hydrocarbon analog, the methylenecyclopropane ring system. 

The rare earth tricyclopentadienyls are insoluble in aliphatic hydrocarbons, and only sparingly soluble in aromatic hydrocarbons. They dissolve in polar solvents like tetrahydrofuran with complexation. Similarly, numerous bases like ethers, amines, isonitriles, phosphines and other compounds react with CP3R, yielding stable 1 1... 

The reactions between W4(OR)i2 (R = CH2Pr , CH2-c-Pent) and the isonitriles RNC (R = Bn, CH2Ph, CeH2Me3-2,4,6) in hydrocarbon solvents yielded /u,4-carbido clusters W4(/Li4-C)(OR)i4 by cleavage of the C=N bond. ° " By contrast, under similar conditions, the tetranuclear alkoxides fail to react with nitriles (MeC N and NC(CH2)sCN) and internal alkynes (MeC CMe, EtC=CEt). 

The dehydration of formamides leads to the formation of nitriles. This reaction can be classified as a homologation reaction, i.e., a reaction bringing about an increase in the hydrocarbon chain of an organic molecule. The transformation corresponds to dehydration to isonitrile, followed by rearrangement of the latter to nitrile. 

AIBN initiates the radical addition of RgSnH to vinyl phosphines, the reduction of monochloromethyl polycyclic benzenoid hydrocarbons by PhgSnH, and of the isonitrile intermediate formed in the deamination of amino-acid esters. ... 

The second isonitrile component, axisonitrile-2, of Axinella cannabina is reported by Fattorusso and his co-workers (77) to be (48) based on the aromadendrane skeleton. They have shown that the hydrocarbon formed from axisonitrile-2 on Birch reduction is identical with the hydrogenation product of aromadendrene, whose stereochemistry shown in (57) has... 

The third sesquiterpene isonitrile in Chart 5 has been isolated from the extracts of Acanthella acuta, which also yielded a number of minor compounds 138). The major component, acanthellin-1, proved to have a 4-epi-eudesmane structure (49). The carbon skeleton was deduced by lithium/ethylamine reduction, which afforded a saturated bycyclic hydrocarbon (60) converted into eudalene by drastic dehydrogenation. The i.r. 

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