Tetracyclone, reactions

D. Miscellaneous.—A further study of the reactions of diphenyl-phosphine oxide with tetracyclone has confirmed that the reaction yields the oxide (30) under mild, basic conditions, and that the reaction is thermally reversible. The displacement of halogen from phosphorus by amino-compounds has been used in the synthesis of a number of aminofluoro-phosphine oxides (31), and of A-methyl-AA-bis(dichlorophosphinyl)-amine (32). ... 

The reaction of tetraphenylcyclopentadienone (tetracyclone) with dialkyl phosphites has invoked further interest. Miller has shown that reactions at 20 °C in the presence of sodium bicarbonate lead to products (35) and (36), with phosphorus substituted at carbon rather than oxygen. Quite different products (37) and (38) are obtained at 160 °C, although whether (38) is obtained from initial attack at oxygen or carbon is still unresolved. 

Ru3(CO)10(Ph2C2)2, and Ru3(CO)9(C2(Ph)2)3 (128). The dinuclear complex Ru2(CO)6(C2Ph2)2, containing a metallocyclopentadiene ring similar to that observed for both iron and osmium, is a further product in the reaction this does imply very similar structures for the trinuclear adducts to those observed for iron and osmium. The carbonyl reacts with tetracyclone to yield the complex Ru3(CO)i0(C2Ph2)2, which may be related to the osmium compounds discussed later. Phosphine substitution of the carbonyls in some of these compounds has been established. 

Some unusual syntheses of substituted 2,2 -bipyridines deserve mention. Tetracyclone (tetraphenylcyclopentadienone) on heating with picolinonitrile at 215°C affords 3,4,5,6-tetraphenyl-2,2 -bipyridine, whereas 5-methyl-2,2 -bipyridine and some polysubstituted 2,2 -bipyridines are obtained by the oxidative degradation of the antibiotic streptonigrin. 5-Aldehydo-6-amino-2,2 -bipyridines are obtained by acid hydrolysis of pyrido[2,3-[Pg.311]

Pentaarylcyclopentadienols (375) are reported to yield endoperoxides (376) which when heated or treated with acids decompose to tetraarylfurans and the corresponding aryl acids.251 Tetraarylsubstituted cyclopentadienones such as tetracyclone (378) lead to m-diaroylstil-benes and carbon monoxide.252-255 Probably, as with other cyclopentadienes, endoperoxides are the primary products. However, no attempts seem to have been made to elucidate the mechanisms of rearrangements and decompositions involved in these reactions. 

Diethyldiphenylcyclopentadienone reacts with 3,5-dinitrophenyl azide on heating to give a pyrid-2-one in a similar reaction with phenyl azide, also suggested to proceed via the nitrene, a bridged intermediate (684) is formed (77TL2463). A different adduct (685) was isolated from the reaction between phthalimidonitrene and tetracyclone when treated with... 

Substituted cyclopentadienones react with iron carbonyls to form stable, diamagnetic 7r-co triplexes of the type [Fe(CO)3(cyclopentadienone)] (215). The proposed structure is shown in (XX). These complexes undergo reactions typical of metal carbonyls, e.g., displacement of carbon monoxide by tertiary phosphines, but the carbonyl group of the ligand does not show reactions characteristic of a keto-group. These complexes are also formed by interaction of acetylenes with iron carbonyls (see Section VI,C). Interaction of tetracyclone and Fe3(CO)i2 gives unstable complexes which contain the sandwich anion [Fe(tetracyclone)2]2 analogous to the anion (XXV) (215). 

Manganese carbonyl, Mn2(CO)io, when treated with tetracyclone at 140-150°, gives an air-sensitive product which on hydrolysis gives the T-cyclopentadienyl complex (LII) 215). Manganese carbonyl does not react with dimcthylacetylene in sunlight, but duroquinone was formed in a similar reaction of the alkyne with [Mn(CO)6] 1 155). Mn(—1) is iso-electronic with Fe(0), and it is suggested that the unstable quinone com-... 

A further method for the synthesis of o-diaroylbenzenes has been described by Ried and Bdnninghausen. Tetracyclone (145), a potent diene for Diels-Alder reactions, together with dibenzoylacetylene (146) gives 147. This method has proved of value in a number of other cases and is also applicable when the cyclopentadienone derivative is dimeric ° as in the case of 2,5-dialkyl-3,4-diarylcyclopentadienones. °... 

The photolysis of zwitterion 8, a stable 1 1 adduct formed by the reaction between phosphorus trisdimethylamide and tetracyclone in benzene solution, affords 1,2,3,4,5-pentaphenylcyclopenta-1,3-diene (9) (equation 6)33. 

When dihydropyrazoline 6 (stereochemistry unknown, but probably exo) was heated in the presence of copper powder to 180°C (or 200°C as stated in experimental) in addition to pyrazole (7) a resinous residue was obtained which was described as a polymer (8) of the then-unknown isobenzofuran 2. The transient existence of 2 was proved by Fieser and Haddadin in 1964 (64JA2081 65CJC1599). Refluxing the Diels-Alder adduct of 1,4-dihydro-1,4-expoxynaphthalene 9 and tetracyclone (10, stereochemistry of the cy-clopentenone moiety unknown see also 71TL2337) in the presence of 9 yields 12 (exo,exo) and 13 (exo,endo there is a misprint in the experimental section of 65CJC1599) in 91% overall yield (12/13 = 42/58). For the reaction of 2 with 9 see also Meier et al. (97LA663). 

In the synthesis of the bisdienophilic phthalocyanine 102, a Diels-Alder reaction of a reactive isobenzofuran (generated by the tetracyclone route) is involved (97CB801). For further work see [95JCS(CC)2449 98ZN(B)1069],... 

Simple bond energy calculations show that 2H- 1,2-oxazines and -thiazines are unstable relative to the corresponding open chain iminoaldehydes and iminothioaldehydes, and thus they only find expression in the form of transient species. Early claims for the synthesis of 2H- 1,2-oxazines have not been authenticated, and, for example, the reaction between 4-nitrosodimethylaniline and tetracyclone does not give the oxazine (1) as was once thought, but rather the isomeric lactam (2), although it is likely that the oxazine is formed as an intermediate (Scheme 1) (64TL1569). 

This double Claisen-Schmidt reaction takes place under the influence of ethano-lic potassium hydroxide (Expt 7.7) and presumably proceeds in the stepwise manner (cf. formulation in Section 6.12.2, p. 1032). The four aryl groups in tetra-cyclopentadienone effectively stabilise the cyclopentadienone system, which otherwise has only a transient existence and readily undergoes dimerisation by way of a diene-dienophile interaction (Diels-Alder reaction, Section 7.6). The use of tetracyclone as a dienophile for the preparation of 3,4,5,6-tetraphenyl-dihydrophthalic anhydride is noted on p. 1121. 

The reaction has been shown to involve a stereospecific syn-addition with respect to the dienophile. For example, the reaction of 2,3-dimethylbuta-1,3-diene with maleic anhydride gives cis-l,2,3,6-tetrahydro-4,5-dimethylphthalic anhydride (Expt 7.20). An example of the use of a quinone as the dienophile is provided by the synthesis of cis-1,4,4a,9a-tetrahydro-2,3-dimethyl-9,l0-anthra-quinone which upon dehydrogenation (most simply by the action of oxygen upon its solution in alcoholic potassium hydroxide) yields 2,3-dimethylanthra-quinone (Expt 7.21). Tetraphenylcyclopentadienone (tetracyclone) readily undergoes the addition of dienophiles, such as maleic anhydride, to give an adduct, which then extrudes a molecule of carbon monoxide on heating, as in the preparation of 3,4,5,6-tetraphenyldihydrophthalic anhydride (Expt 7.22). 

The polymerization reaction is typical of step-growth reactions in that it follows second-order kinetics for the reaction of tetracyclone ends with acetylene ends (Figures 1 and 2). 

The reaction of Hg[Co(CO)4]2 with some terminal alkynes, RC=CH, has given mercury carbonylcobalt-alkyne complexes. Thus, the reaction of RC=CH and Hg[Co(CO)4]2 at 100°C gives complexes of stoichiometry HgCo2(CO)e(RC2H)4. The complex with R = Ph has been isolated also from the reaction of tetracyclone with Hg[Co(CO)4]2 133). The known complexes of this type are listed in Table XII. 

A similar thermal rearrangement has been observed in a two phase reaction when dichlorocarbene is added to tetracyclone giving E (30%). Heating of E in refluxing mesitylene or o-dichlorobenzene for 3.5 hrs gives 60% of 3-chloro-2,4,5,6-tetraphenylphenol123). 

The reaction between acetylenes and ruthenium carbonyls produces a series of n complexes with cyclic ligands which, as in the iron system, have either the metal or a CO group incorporated into the ring. Accordingly, 3-hexyne 536) and hexafluoro-2-butyne 90) react with Ru3(CO)i2 to give the (substituted cyclopentadienone)tricarbonylruthenium complexes with structures presumably comparable to those of the iron complexes (93-95). Although diphenylacetylene will not react directly with Ru3(CO)i2 to produce this type of complex 536), it can be prepared 90) by treating Ru3(CO)i2 with tetracyclone in benzene under reflux. 

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