Heptane reactions with hydrogenation

HEPTANONE or HEPTAN-2-ONE (110-43-0) Forms explosive mixture with air (flash point 102°F/38°C). Violent reaction with strong oxidizers, aldehydes, nitric acid, perchloric acid. A variety of unstable peroxides may be formed from the reaction with hydrogen peroxide. Incompatible with aliphatic amines, aldehydes, strong bases, hydrogen peroxide, nitric acid, perchloric acid. Attacks some plastics and rubber. 

In this process, the metal is catalytic in that it serves as a template for reaction with hydrogen gas and the formation of two new a-covalent C-H bonds. The catalyst facilitates hydrogen transfer to the alkene, but it is regenerated when the cycle is complete. Therefore, only a catalytic amount of the metal is required. The mechanism outlined in Figure 19.1 is used to explain the reduction of 1-heptene to heptane with hydrogen gas and nickel or certain other metals. 

Since hydrogen peroxide, like alkyl hydroperoxides, can be alkylated by alkyl bromide plus silver trifluoroacetate (Eq. 19, R = H),35) an attractive variation of the silver-salt-induced dioxabicyclization uses cis- 1,3-dibromocycloalkane 43 as starting material. Thus Porter and Gilmore obtained 2,3-dioxabicyclo[2.2.1]heptane 9 in 30-40% yield from c s-l,3-dibromocyclopentane, which was itself obtained from the corresponding c/s-diol by reaction with triphenylphosphine dibromide (Eq. 31 R = R = H)36). 

A mixture of exo- and endo-isomers of 5-methylbicylo[2.2.1]hept-2-ene is hydrogenated with the aid of five equivalents of triethylsilane and 13.1 equivalents of trifluoroacetic acid to produce a 45% yield of < <7o-2-methylbicylo[2.2.1] heptane (Eq. 71). The same product is formed in 37% yield after only five minutes. The remainder of the reaction products is a mixture of three isomeric secondary exo-methylbicylo[2.2.1]heptyl trifluoroacetates that remains inert to the reaction conditions. Use of triethylsilane-l-d gives the endo-2-methylbicylo-[2.2.1]heptane product with an exo-deuterium at the tertiary carbon position shared with the methyl group. This result reflects the nature of the internal carbocation rearrangements that precede capture by the silane.230... 

The reaction of AsPhs with Ni/AhOs in n-heptane solution, under hydrogen (12 bar) at between 25 and 200 °C, only takes place on the nickel surface and is characterized by benzene (and cyclohexane, secondary product) evolution [135]. At 80 °C, saturation of the nickel surface has been reached with a ratio As/Nis of 1. At 100 °C, arsenic migration from the nickel surface to the core of the particle is observed. This migration is characterized by a rapid decrease in ferromagnetism of the nickel particles, reaching zero for an As/Ni ofO.45. At 170 °C, NiAs alloy formation has been highlighted by its X rays diffraction pattern (Figure 2.18). 

Reaction of 1,3,3-trihalo-7-oxabicyclo[4.1.0]heptanes 11-14 with hydrogen fluoride/py-ridine results in the regio- and stereoselective formation of the corresponding m-fluoroalkanols in good yield.103... 

The involvement of an intramolecular hydrogen abstraction in the Barton reaction is not necessarily limited to those molecules with rigid stereochemistry. In fact, simple aliphatic nitrites undergo the Barton reaction with equal ease. Thus, the principal product obtained from the photolysis of ra-octyl nitrite20 in benzene solution is the dimer of 4-nitroso-l-octanol however, photolysis of n-octyl nitrite in n-heptane20 produced a mixture of 7/-nitroso heptanes in addition to 4-nitroso-l-octanol in the ratio l 4.5,f respectively. The formation of y-nitroso heptane obviously results from an attack of the intermediate alkoxy radical on the solvent molecule. The intermediate alkyl radical then collapses, according to eq. 2. For the sake of convenience we have indi-... 

Catalyst C is obtained by reaction of Sn(n-C4Hg)4 with B in the liquid phase (n-heptane) under a hydrogen atmosphere (vide supra). The amount of tin fixed on the catalyst depends on the amount of Sn(n-C4H9)4 introduced (Table 1). 

Recently, Rooney and co-workers (23,58,59) have questioned the view that triadsorption by loss of 3 hydrogen atoms from the alkane is the minimum requirement for bond-shift reactions. They studied the isomerization of a series of caged hydrocarbons in excess hydrogen on palladium and platinum catalysts. The compounds were chosen in order to render difficult or totally exclude a mechanism involving aory-triadsorbed species. Thus, l,7,7-trimethyl[2,2,l]-heptane interconverts with its endo- and exo-2,3,3-trimethyl isomers, bicyclo-[3,2,2] octane changes to bicyclo[3,3,l] nonane, and protoadamantane to... 

Table 5 shows the composition of the solvents subjected to preheat, the solvent composition based on the percentage of preheated solvent in the total reaction solvent and the composition of the heptane solubles isolated from each reaction. The data shows that the preheated solvents are reduced in percent hydrogen and hydrogen to carbon ratio with increasing severity of preheat. The hydrogen to carbon ratio of the heptane solubles after reaction with coal is essentially the same as that of the solvent (92-03-035 + preheated solvent) which reacted with coal. 

Even in the early days of homogeneous hydrocyanation the reaction of norbor-nene with hydrogen cyanide in the presence of tetrakisftriphenyl phosphite)palla-dium(O) 12 indicated the influence of steric factors, since exo-5-cyanobicy-clo[2.2.1]heptane (Structure 10) is obtained stereospecifically. This result was confirmed in similar reactions showing that the entering cyano group is directed into the exo-position of the norbomene system [28]. This is due to the complexa-tion of the palladium(O) center to the exo-face of norbomene. Recent experiments have also utilized the bicyclic system to demonstrate asymmetric hydrocyanation induced by chiral palladium diphosphine complexes. Depending on the applied ligand system 11-17, an enantiomeric excess (ee) up to 40% is obtained [25]. 

The reaction of bicyclo[4.1.0]heptane with diborane and subsequent treatment with hydrogen peroxide produced predominantly cyclohexylmethanol (5b) in high yield.Under modified experimental conditions small amounts of isomeric methylcyclohexanol (6b) and cycloheptanol (7b) were isolated. In contrast to the hydroboration of alkenes, the cyclopropane cleavage reaction is inhibited by ethereal solvents such as diethyl ether, tetrahydrofuran or 2-methoxy-ethyl ether. Bicyclo[3.1.0]hexane reacted with diborane in a similar fashion to give mainly cyclopentylmethanol (5a).The reaction of l-methylbicyclo[4.1.0]heptane gave a mixture of cis- and tram-(2-methylcyclohexyl)methanol (5c) in an initial ratio of 60 40. Spiro[2.5]octane reacted with diborane to yield only products derived from scission at the spiro carbon. The main product was 2-cyclohexylethanol (8). ... 

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