Tetrachloro-o-quinone

Trans oxidative addition of CH3I to [Ir(acac)(cod)] affords the structurally determined complex [Ir(acac)(cod)(CH3)1].241 The reaction of [(Npet)2Ir]Cl, Npet = o-(diphenylphosphino)benzylide-nejethylamino, with tetrachloro-o-quinone yields the structurally characterized product (135).242 The synthesis and characterization of the water-soluble complex (136) have been described.243... 

Treatment of the salt, [PhsBiCFhCOR1] BF4 with base generates triphenylbis-muthonium 2-oxoalkylide (84 R1 = Buf, Ph). This reacts with 1,2-dicarbonyls to give 2,3-diacyloxiranes (85 from acyclic reactants, MeCOCOR2, R2 = Me, OEt) or 2-acyl-3-hydroxytropones [e.g. (86), from the tetrachloro-o-quinone].123 Both reaction types are of considerable synthetic utility, and both are in marked contrast to the routes followed by the corresponding phosphonium ylids. 

The reactions of P-halophospha-alkenes with carbenes provide a new route to 1-chloro-lH-phosphirines (181). Such compounds are highly reactive, and a study of nucleophilic displacement reactions at phosphorus has been facilitated by preparation of the related P-W(CO)5 complexes.The first pentacoordinate systems derived from phosphirenes, (182), have been formed in the reactions of P-halo- or P-cyano-phosphirenes with tetrachloro-o-quinone. Evidence has been presented for the rearrangement of P-chlorophosphirenium ions (183) to the vinylphosphenium ions (184)... 

Carbenes, generated by photolysis of di- and tetrachloro-o-quinone diazides, react with oxetane in a 1 3 ratio to afford 15-membered crown ethers. Benzocrown ether 675 was obtained in 16% yield (91CB1865). Derivatives of macrocyclic crown ethers with four or five oxygen atoms in a ring were synthesized by Cu(acac)2-catalyzed cyclization of a,polyethylene glycols. 20-26-Membered crown-4(5) ethers 676 were prepared from the above-mentioned diazo ketones with tri- or tetra-ethylene glycols in 7-26% yields. Treatment of l,8-bis(diazoacetyl)octane with dodecane-l,12-diol under the same conditions results in a mixture of 52-membered tetraether 646 (40%) and compound 645 (81CC616). 

Tetramethyl-tetralindione (73) Tetrachloro-o-quinone n-Butyraldehyde ), benzaldehyde 15>, anisaldehyde ls), />-chlorobenzaldehyde 151 Acetaldehyde Benzaldehyde 14 ), p-tolualdehyde 145>, anisaldehyde 145 cinnamaldehyde 14B>... 

Also, chlorine was found to convert o-benzoquinone into tetrachloro-o-quinone. 

The tetrachlorocatecholatovanadium(IV) complex [VO(acac)(TCC)], obtained by reacting V0(acac)2 with tetrachloro-o-quinone (TCQ), has... 

Photolysis of [CrfCOje] in the presence of tetrachloro-o-quinone gives... 

DDQ has proved to be the most versatile of the high-potential quinones although certain others, notably chloranil (previous section) and tetrachloro-o-benzoquinone have been used on occasion. 

The reactivity of stable germaphosphenes has been previously investigated and reviewed.3,4,7 The chemical behavior of Mes2Ge = PAr 155 toward orthoquinones (tetrachloro-o-benzoquinone, 3,5-di-terr-butyl-o-benzoqui-none, and 1,2-naphthoquinone) and ce-diketones (benzil and biacetyl) has been examined. The reaction with o-quinones involved probably radical intermediates, and in each case only the less encumbered isomer of the corresponding [2 + 4] cycloadduct 156 was formed. Benzil led in a very similar manner to a l,4,2,3-dioxagermaphosphin-5-ene 157, whereas, as was observed with acetone, an ene-reaction occurred with biacetyl to afford 158138 (Scheme 29). 

Reacts with amines and alkali metals forming the corresponding water-soluble salts (Sanborn et al, 1977). Reacts with nitric acid forming a mixture of tetrachloro-o and p quinones (Monsanto, 1963). 

HjCat represents catechol or hydroquinone, Q quinone, SQ semiquinone anion, HCat- catechol monoanion, and Cat2 catechol dianion DTBQ represents 3,5-di-rerr-butyl-o-quinone, o-Q o-benzoquinone, p-Q p-benzoquinone, TCQ tetrachloro-o-benzoquinone, and TFQ tetrafluoro-o-benzoquinone. 

The oxidation of 2-iodo-l,3,2-diheteroarsolanes by tetrachloro-o-benzo-quinone has been studied by Wieber and Gotz (193). In this reaction the cleavage of the As—I bond occurred with the formation of spirocyclic arsoranes ... 

Tetrachloro-p-quinone (1.2 g) and 3-N,N-diethylaminophenol (1.80 g) were dissolved in 50 ml methyl alcohol, 4.2 ml 28% aqueous solution sodium methoxide added, and the mixture refluxed 6 hours. Thereafter, the mixture was extracted with CH2CI2, dried, and concentrated. The product was purified by chromatography on silica gel using chloroform/hexane and cis- and trans-products, 0.42 g and O.lOg, mp = 292 °C and 288 °C isolated, respectively. H-NMR and absorption maxima and coefficients data supplied. 

Very selective oxidizing agents suitable for the conversion of primary alcohols into aldehydes are high-potential quinones such as tetrachloro-o-benzoquinone, tetrachloro-p-benzoqninone, and 2,3-dichloro-5,6-dicyano-p-benzoquinone [973]. Such dehydrogenations are carried out in chloroform, carbon tetrachloride, or ethanol, usually under very mild conditions at room temperature or in refluxing ether, and give fair to good yields (equation 216) [973]. 

Dioxaphospholens.—4-Trityl-o-benzoquinone has been condensed with phosphites to give pentaoxyphosphoranes. With tetrachloro-o-benzo-quinone the chiorophosphine (37) gave an adduct formulated as (38). 1 1 Adducts of hexafluorobiacetyl with trimethyl phosphite, the caged phosphite... 

The photoaddition of sulfur dioxide to o-quinones in benzene solution to produce cyclic sulfates (26) in fair to high yields was reported by Schenck and Schmidt-Thomee 1431 in 1953. Products were obtained from tetrachloro-o-benzoquinone, 1,2-naphthoquinone, 3-nitro-l,2-naphtho-... 

A lesser degree of loss of configuration was observed in the reactions of cis- 36> and iraMS-stilbene 35> with tetrachloro-o-benzoquinone to give dioxenes. The m-stilbene reaction (in acetone or acetonitrile) afforded about 80% of cis-adduct while 88% of trans-a.d6.net 35> was obtained from the reaction of trans-stilbene (both reactions at 15°, A >400 nm). Curiously, irradiation of the quinone and cfs-stilbene (or diphenyl-acetylene) in benzene solution produced the mono-phenyl ether (33)... 

Photochemistry of diones began with Klinger s 82> report of the sunlight reactions of benzil and phenanthrenequinone with diethyl ether but reactions of diones with ethers have been investigated to a very limited extent since then. The reported reactions include biacetyl (dioxane 20>), benzil (diethyl ether 82>, dioxane 128>), tetramethyltetralindione (73, dioxane 60>), tetrachloro-o-benzoquinone (dioxane 128>), acenaphthene-quinone (dioxane 128>) and phenanthrenequinone (diethyl ether 82>, di-isopropyl ether 127>, di-n-butyl ether 127>, tetrahydrofuran 128>, dioxane 128>, anisole 128>, methoxycholestane (86) 128>, methoxy-5-cholestene 128>). 

The thermal and photochemical [4 + 2] cycloadditions of o-quinones with olefinic and acetylenic dienophiles have been extensively reviewed4,5,200 and include their 4tt heterodiene Diels-Alder reactions with olefins,201-204 vinyl ethers,205 enamines,206 selected dienes,207-209 dipheny-lketenimines,210 ketenes,209,210 fulvenes,211 and selected heterocycles including furan,207-209,212 benzofuran,209,212,215 indoles,213 azepines,214 and 1,2-diazepines.214 The tetrahalo-substituted o-quinones, tetrachloro- and tetrabromo-o-quinone, generally participate in heterodiene [4 + 2] cycloadditions at an increased rate over the unsubstituted systems and generally provide higher overall yields of the Diels-Alder products.4,5 With simple olefins, the dienophile geometry is maintained in the course of the thermal [4 4- 2] cycloadditions [Eq. (52)],203,204... 

DEHYDROGENATION Palladium black. Potassium-Graphite. Tetrachloro-o-benzo-quinone. 

Chloro carbonyl(tetrachloro-o-semi-quinone bis(triphenylphosphine))iridium(III) Nr.ll7, X = Ir... 

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