Tetracyanoethylene oxide, reaction with

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 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... 

The zwitterion (6) can react with protic solvents to produce a variety of products. Reaction with water yields a transient hydroperoxy alcohol (10) that can dehydrate to a carboxyUc acid or spHt out H2O2 to form a carbonyl compound (aldehyde or ketone, R2CO). In alcohoHc media, the product is an isolable hydroperoxy ether (11) that can be hydrolyzed or reduced (with (CH O) or (CH2)2S) to a carbonyl compound. Reductive amination of (11) over Raney nickel produces amides and amines (64). Reaction of the zwitterion with a carboxyUc acid to form a hydroperoxy ester (12) is commercially important because it can be oxidized to other acids, RCOOH and R COOH. Reaction of zwitterion with HCN produces a-hydroxy nitriles that can be hydrolyzed to a-hydroxy carboxyUc acids. Carboxylates are obtained with H2O2/OH (65). The zwitterion can be reduced during the course of the reaction by tetracyanoethylene to produce its epoxide (66). 

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). 

Oxide 1 reacts with tetracyanoethylene (TCNE) to give the 1 1 adduct 275. Its structure was determined by X-ray crystallography.164 The reaction is believed to proceed through the prior isomerization of the oxide to phenanthrone, followed by its reaction with TCNE as shown in Scheme 2. The... 

The unexpected formation of the blue crystalline radical cation (97) from the reaction of triazinium salt (98) with tetracyanoethylene has been reported and the product identified by its EPR spectrum and by X-ray crystallography (Scheme 42).199 Carboxylic acids react with the photochemically produced excited state of N-t-a-phenynitrone (PBN) to furnish acyloxy spin adducts RCOOPBN. The reaction was assumed to proceed via ET oxidation of PBN to give the PBN radical cation followed by reaction with RCO2H.200 The mechanism of the protodiazoniation of 4-nitrobenzenediazonium fluoroborate to nitrobenzene in DMF has been studied.201 Trapping experiments were consistent with kinetic isotope effects calculated for the DMF radical cation. The effect of the coupling of radicals with different sulfur radical cations in diazadithiafulvalenes has been investigated.202... 

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). 

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. 

Treatment of thietane with electron acceptors, such as tetracyanoquino-dimethane (TCNQ), tetracyanoethylene (TCNE), maleic anhydride, or tetra-nitromethane, induces polymerization, believed to occur through an intermediate charge-transfer complex. The reaction with tetranitromethane is unusual because nitric oxide, nitrogen dioxide, carbon monoxide, ethylene, ethane, and propane are... 

Compounds with aliphatic olefins or with diolefins have been easily obtained by reaction of Pt(PPh3)2 with the olefins, octene, n-pentene, butadiene, and cycloocta-1,5-diene 187). They are white, stable to oxidation, and exchange the olefin with other ligands easily. Tetracyanoethylene (C6N4) derivatives of the type Pt(PR3)2(CeN4) (R = Et, Ph) have been obtained recently (7) by different reactions—i.e., from tetrakis(triphenyl-phosphine)-platinum(O) or rans-PtHCl(PR3)2 and tetracyanoethylene, or from Pt(PPh3)2(alkyne) and tetracyanoethylene. The compounds with the latter ligand are always more stable than the compounds with other olefins. 

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). 

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