Tetracyanoethylene oxide reactions

Tetracyanoethylene oxide [3189-43-3] (8), oxiranetetracarbonitnle, is the most notable member of the class of oxacyanocarbons (57). It is made by treating TCNE with hydrogen peroxide in acetonitrile. In reactions unprecedented for olefin oxides, it adds to olefins to form 2,2,5,5-tetracyanotetrahydrofuran [3041-31-4] in the case of ethylene, acetylenes, and aromatic hydrocarbons via cleavage of the ring C—C bond. The benzene adduct (9) is 3t ,7t -dihydro-l,l,3,3-phthalantetracarbonitrile [3041-36-9], C22HgN O. 

The only other dipolar species that has been added to thiophene is the carbonyl ylide (287). Thus tetracyanoethylene oxide, as the carbonyl ylide, reacts with thiophene to form the adduct (288) in 70% yield (65JA3657, 68T2551). Several monosubstituted thiophenes have been used in this reaction. From competitive experiments it has been shown that the rate of cycloaddition to furan and benzo[6]furan is greater than that to thiophene and benzo[6]thiophene respectively (75ACS(B)441). 

Linn and Benson discovered in 1963 the ability of tetracyanoethylene oxide (145) to react with alkenes and alkynes at elevated temperatures in [3 + 2] cycloadditions.139 The kinetics of the reaction of (145) with styrene revealed that the formation of (147) is preceded by a first-order step consisting of the electrocyclic ring opening to the carbonyl ylide (146 Scheme 33). 

The decomposition of (18) in the presence of electron-deficient oxygen acceptors such as tetracyanoethylene forms the tetracyanoethylene oxide (19)51, with 60% yield. The oxygen atom transfer may be considered a general reaction of carbonyl oxides in ozonolysis of C=C double bonds when oxygen-accepting substrates are present. 

Naphthyridine with tetracyanoethylene oxide gave l,6-naphthyridin-6-ium-6-dicyanomethanide (12) (substrate, THF, <5°C synthon/THFJ, dropwise, <5°C, 24 h 63%) 857 also analogous reactions.101,857... 

In a subsequent investigation it was observed that the reaction of tetracyanoethylene oxide with 5,10,15,20-tetraphenylporphyrin-zinc chelate produced the corresponding zinc chelated derivative of 5,10,15,20-tetraphenyl-2,3-(3 -dicyano)cyclopropano-2,3-chlorin and is described by the author (4). 

Other reactions of tetrasubstituted azomethyne ylides prepared from tetracyanoethylene oxide are described, I, (5). 

Cyclohexene oxide reacts with 402 to afford 403 . Reaction of tetracyanoethylene oxide with low-valent metal complexes [Pd(PAr3) ] (Ar/n = Ph/4, Tol/3) or [Pt(PPh2Me)4] leads to complexes 404 . ... 

In an attempt to synthesize fused aromatic systems of a pentalene-like structure, Boekelheid and Fedoruk (332) submitted the dicyanomethyl ylide of thiazole (77) to the addition reaction with dimethyl acetylenedi-carboxylate (DMA). They unexpectedly observed the formation of a fused six-membered (80) rather than a five-membered-ring (78). This ylide (77) was readily afforded by the reaction of thiazole (73) with tetracyanoethylene oxide and then put into reaction with DMA. The initially formed thiazolopyrrole derivative (78) is strongly polarized by the gcm-dicyano group, and its pyrrole ring is spontaneously cleaved with proton elimination. The ring dosure of the intermediate (79) leads to the final stable derivative of 5-FT-thiazolo[3,2-a]pyridine (80). More recently. 

Methylation (666, 912) of 2-methoxypyrazine with methyl iodide in dimethyl sulfoxide at room temperature gave 3-methoxy-l-methylpyrazinium iodide with a rate of methylation relative to pyrazine of 1.05 (666). 2-Methoxypyrazine with tetracyanoethylene oxide gave a small yield of 3 ethoxypyrazinium dicyano-methylide (53) (1094). Alkylation of 2-methoxypyrazine with ethyl methyl ketone in the presence of sodium in liquid ammonia to give 2-s-butyl-6-methoxypyrazine (17%) has been described (614). The reactions of 3-hydroxy-2,5-dimethylpyrazine and alkylhalides have been examined (1095). 

Triazinium 2-dicyanomethylides 4 were readily prepared by reaction of 1,2,3-triazines 1 with oxiranetetracarbonitrile (tetracyanoethylene oxide) in tetrahydrofuran at room temperature.47 228... 

The synthesis of pyrrolonaphthyridine derivatives has been reported from 1,3-dipolar cycloaddition reaction of naphthyridinium dicyanomethylides with DMAD. Starting from [1,5]- and [1,8]-naphthyridines (139), dicyanomethylides (140) were prepared on treatment with tetracyanoethylene oxide (TCNEO) in THE and they underwent 1,3-cycloaddition with DMAD in acetonitrile to afford aromatic products (142) after elimination of HCN from the adducts (141) (Scheme 18). Pyrrolo[2,l-/]naphthyridine (143) was obtained when the N-6 dieyanomethylide of [l,6]-naphthyridinium was employed <93H(36)1945>. 

New Applications of Tetracyanoethylene (TCNE) in Organic Chemistry, A. J. Fatiadi (1986). This review with 501 references deals with reactions of tetracyanoethylene used in organic synthesis. Information on molecular complexes, ozonization of alkenes and acetylenes, dehydrogenation and tricyanovinylation, reactions of TCNE oxide, reactions with ketones and diketones, synthesis of heterocycles and cationic polymerizations are included in this survey. Some industrial and analytical applications are also discussed. 

Tetracyanoethylene oxide is a potent enophile which often behaves as a 1,3-dipolar species. It is remarkable that benzene is attacked resulting in a cyclo-hexadiene derivative (54). The normal course can be diverted to a competing 0-transfer process, however, when the olefin s reaction partners are very soft (55). 

S. Gronowitz and B. Uppstrom, On the reaction of 2,5-dihalothiophenes with tetracyanoethylene oxide, Acfa Chem. Scand., B28, 981-985 (1974). 

The reaction of SchifF bases with tetracyanoethylene oxide generates the ylides (98) which may be trapped by reaction with dipolarophiles, e.g. with iV-phenylmaleimide, (99) is formed. ... 

Tetracyanoethylene oxide can act to oxidize sulfides to sulfoxides but also reduces sulfoxides to sulfides with generation of two molecules of carbonyl cyanide. In its reaction with 3,4-di-fert-butylthiophene 1-oxide, the Diels-Alder adduct was found to be the major product, instead of the reduced product 3,4-di-ferf-butylthiophene, because the reaction proceeded through intermediate 49 instead of 48 (Scheme 45) [50],... 

Dialkylthioketenes undergo [3+2] cycloaddition reaction with tetracyanoethylene oxide. However, the cycloadducts 54 undergo cycloreversion and rearrangement to give allene episulfides 55. ... 

Tetracyanoethylene oxide reacts with pyridine, giving l-(dicyanomethyl-ene)pyridinium 248 and with 2-pyridone di-(trifluoromethyl) acetylene gives l-(di-trifluoromethyl)vinyl-2-pyridone 249, jn the same reaction... 

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