Nitrocyclohexane , reaction

Double Michael addiQoas of rutro compounds beanng tethered acidic carbons to 3-butyn-3-one under NaH catalysis give nitrocyclohexanes v/ith high stereoselectivity The products are transformed into rrruii -fused bicyclic compounds via the Dickmarm reaction on treatment with base fEq 4 139 ... 

Nitroalkenes are good candidates for the rhodium-catalyzed asymmetric 1,4-addition of organoboronic acids. Hayashi et al. reported that the reaction of 1-nitrocyclohexene with phenylboronic acid in the presence of rhodium/ -BINAP catalyst gave 99% ee of 2-phenyl-1-nitrocyclohexane (Scheme 38).117... 

In addition to the present method,2 1-amino-1-methylcyclo-hexane has been synthesized by the following procedures Ritter reaction, e.g., with 1-methylcyclohexanol (76%, 67%)3i 4 or 1-methylcyclohexene (35%,) 4 5 Hofmann reaction with 1-methyl-cyclohexanecarboxamide (80% as hydrochloride) 6 reduction of 1-methyl-l-nitrocyclohexane (63%) 6 Schmidt reaction with 1-methylcyclohexanecarboxylic acid (42%).6... 

In a recent application of this strategy, nitrocyclohexane 143 (prepared from nitrosugar 142 by intramolecular Henry reaction) was subjected to a radical denitration by HSnBu3, after protection of the hydroxyl groups to avoid side reactions. Inositol 146 was selectively obtained in good yield, once the hydroxyl protecting groups were removed (Scheme 45).101... 

For the cyclization of dialdehydes, however, its utility seems limited. Being a nitromethane addition product, it can readily undergo retro-nitromethane addition with alkali to give formaldehyde and nitromethane. Thus, it is not surprising that reaction of glutaraldehyde with 2-nitroethanol under the usual conditions (i.e. 1 molar equivalent of sodium hydroxide in aqueous ethanol) should yield 2-nitrocyclohexane-1,3-diol 5), a nitromethane cyclization product With catal5dic amounts of sodium hydroxide (pH 8—9), however, 1-hydroxymethyl-l-nitro-cyclohexane-2-6-diol (80) can be isolated in yields of 24—29%... 

Reaction of 1-nitropropane with glutaraldehyde in aqueous ethanol in the presence of sodium hydroxide yields a mixture of two products, the major component of which, lr-ethyl-l-nitrocyclohexane-2c,6f-diol (98), can be isolated in 36% yield ). Acid-catalyzed acetylation converts (98) into the di-O-acetate, hydrogenation yields the corresponding amine, which has been characterized as the hydroacetate, N-acetate and triacetate. Configurational assignments followed from NMR data, which clearly showed the steric non-equivalence of the two hydroxyl groups vicinal to the tertiary center. 

Alkynyl(phenyl)iodonium salts can be used for the preparation of substituted alkynes by the reaction with carbon nucleophiles. The parent ethynyliodonium tetrafluoroborate 124 reacts with various enolates of /J-dicarbonyl compounds 123 to give the respective alkynylated products 125 in a high yield (Scheme 51) [109]. The anion of nitrocyclohexane can also be ethynylated under these conditions. A similar alkynylation of 2-methyl-1,3-cyclopentanedione by ethynyliodonium salt 124 was applied in the key step of the synthesis of chiral methylene lactones [110]. 

Yamaguchi et al. also showed that Rb-L-prolinate catalyzes enantioselective addition of nitroalkanes to several acyclic and cyclic enones [25, 26]. For acyclic enone acceptors the best result, i.e. 74% yield and 68% ee of the S product, was achieved in the addition of 2-nitropropane to -3-penten-2-one (40a, Scheme 4.13) [25]. Screening of several proline derivatives and cyclic amino acids of other ring size resulted in the identification of the O-TBDMS-derivative of 4-hydroxyproline as the best catalyst for addition of nitrocyclohexane to cycloheptenone. In this particular reaction 74% yield and 86% ee were achieved [26]. 

The catalytic oxidation of cyclohexane is performed in the liquid phase with air as reactant and in the presence of a catalyst. The resulting product is a mixture of alcohol and ketone (Table 1, entry 12) [19]. To limit formation of side-products (adipic, glutaric, and succinic acids) conversion is limited to 10-12 %. In a process developed by To ray a gas mixture containing HC1 and nitrosyl chloride is reacted with cyclohexane, with initiation by light, forming the oxime directly (Table 1, entry 12). The corrosiveness of the nitrosyl chloride causes massive problems, however [20]. The nitration of alkanes (Table 1, entry 13) became important in a liquid-phase reaction producing nitrocyclohexane which was further catalytically hydrated forming the oxime. 

The reactions of the stereo-pair of a-chloro nitrocyclohexanes 82 and 83 with a nitronate anion gave identical proportions of the epimeric substitution products (equation 70). This... 

Because the hydrogen atom and phenyl group migrate so readily, the reactions of / -dicarbonyl enolates with ethynyl- and (phenylethynyl)iodonium salts can be expected to result in alkynylation. It has already been noted that the 2- -hexyl-l,3-indandionate ion undergoes alkynylation with (phenylethynyl)phenyliodonium tetrafluoroborate (equation 43), despite the availability of the -hexyl group for [2 + 3] annulation. Ethynylations of six / -dicarbonyl enolates and the anion of 2-nitrocyclohexane with ethynyl(phenyl)-iodonium tetrafluoroborate in THF have also been reported27. For example, admixture of the ethynyliodonium salt and the anion of ethyl 2-cyclopentanone-l-carboxylate in THF affords the 1-ethynyl derivative in 71% isolated yield (equation 124)27. 

Scheme 9A Formation of cyclohexanone from aci-nitrocyclohexane by the Nef reaction.

MCPBA has been regarded as the reagent of choice for the conversion of primary aliphatic amines into the corresponding nitro compounds. The peroxy acid must be used in excess to minimize formation of dimers of the intermediate nitroso compounds, llie yield of nitroalkane is also increased if the reaction is carried out at elevated temperature, since this favors the monomeric rather than the dimeric foim of the intermediate nitrosoalkane and allows it to be oxidized further. For example, cyclohexylamine gave the dimer of nitrosocyclohexane (43%) when oxidized by MCPBA at 23 C, but at 83 C (in boiling 1,2-di-chloroethane) the only product was nitrocyclohexane (86%). 

Titanium(II) reagents have also been used to reduce aliphatic nitro compounds to amines halo, cyano and ester groups are not reduced. Sodium borohydride, in the presence of catalytic amounts of nickel(II) chloride, reduces a variety of aliphatic nitro compounds to amines. Nickel boride (Ni2B) is an active catalyst for reductions of primary, secondary and tertiary nitro aliphatic compounds to amines. The reduction of nitrocyclohexane (45) yields cyclohexylamine (47) as well as small amounts of dicyclohexylamine (49), the latter being formed via reaction of intermediates (46) and (48 equation 28). 

Good yields were also obtained in the reaction of vinyllead derivatives, generated from the trimethyltin derivatives, with the sodium salts of 2-nitropropane or of nitrocyclohexane. ... 

Surprisingly, the actual rates of axial and equatorial entry of X in (216) need not be very different This becomes understandable in the context of a conformational analysis (Bordwell and Vestling, 1967). We use proton abstraction from nitrocyclohexanes and the reverse reaction (see (212)) to investigate the origins of SS. The scheme of Fig. 27 may be helpful here. For the deprotonation of the 4-t-butyl-nitrocyclohexanes of (212), R=H and (114)/ (113) 5 the equilibrium constant K = (114)/(113) 1/5 (Bordwell and Vestling, 1967). Therefore, the free energy difference for the transition states, Gf13 — 0. 

NITROCYCLOHEXANE (1122-60-7) C4H N02 Highly flammable liquid. Forms explosive mixture with air (flash point 166°F/74°C Fire Rating 3). An oxidizer. Violent reaction possible explosion, especially at high temperature and pressure ... 

A general procedure for conversion of substituted benzyl halides into aldehydes consists in their reaction with the sodium salts of aliphatic nitro compounds, particularly those of 2-nitropropane and nitrocyclohexane which afford unstable ester-like intermediates with benzyl halides the intermediates decompose to oxime and aldehyde ... 

We found that Michael addition of nitroalkanes had limited success with nitromethane owing to its nitroaldol reaction with the products formed from methyl vinyl ketone and cyclohexenone, for example. (It may be noted in this regard that although the product obtained in the reaction of methyl vinyl ketone with nitromethane was achieved in 78% yield [127], a recent report [128] described a 98 % yield by employing the less basic catalyst TBD at a higher temperature 0°C). However, 2-nitropropane and nitrocyclohexane were much better candidates for pro-azaphosphatrane-catalyzed reactions for which DBU and TMG typically require longer reaction times and afford only poor to modest product yields [127]. 

Nitrogen Compounds. The aqueous Oxone-acetone combination has been developed for the transformation of certain anilines to the corresponding nitrobenzene derivatives, as exemplified in eq 15. This process involves sequential oxidation steps proceeding by way of an intermediate nitroso compound. In the case of primary aliphatic amines, other reactions of the nitrosoalkane species compete with the second oxidation step (for example, dimerization and tautomerization to the isomeric oxime), thereby limiting the synthetic generality of these oxidations. An overwhelming excess of aqueous Oxone has been used to convert cyclohexylamine to nitrocyclohexane (eq 16)P... 

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