Primary alkyl groups

Ethyl (CH3CH2—) heptyl [CH3(CH2)5CH2—] and octadecyl [CH3(CH2)i6CH2—] are examples of primary alkyl groups... 

Those derived from isobutane are the 2 methylpropyl (isobutyl) group and the 1 1 dimethylethyl (tert butyl) group Isobutyl is a primary alkyl group because its poten tial point of attachment is to a primary carbon tert Butyl is a tertiary alkyl group because Its potential point of attachment is to a tertiary carbon... 

Friedel-Crafts acylation followed by Clemmensen or Wolff-Kishner reduction is a standard sequence used to introduce a primary alkyl group onto an aromatic ring... 

Potential energy diagram (Section 4 8) Plot of potential en ergy versus some arbitrary measure of the degree to which a reaction has proceeded (the reaction coordinate) The point of maximum potential energy is the transition state Primary alkyl group (Section 2 13) Structural unit of the type RCH2— in which the point of attachment is to a pnmary carbon... 

Primary alkyl groups are more reactive than secondary and tertiary. PivaUc acid accelerates the rate of protonolysis of trialkylboranes with water and alcohols (207,208). The reaction can be controlled to give excellent yields of dialkylbotinic acids and esters. 

The reactions of trialkylboranes with bromine and iodine are gready accelerated by bases. The use of sodium methoxide in methanol gives good yields of the corresponding alkyl bromides or iodides. AH three primary alkyl groups are utilized in the bromination reaction and only two in the iodination reaction. Secondary groups are less reactive and the yields are lower. Both Br and I reactions proceed with predominant inversion of configuration thus, for example, tri( X(9-2-norbomyl)borane yields >75% endo product (237,238). In contrast, the dark reaction of bromine with tri( X(9-2-norbomyl)borane yields cleanly X(9-2-norbomyl bromide (239). Consequentiy, the dark bromination complements the base-induced bromination. 

All lation. In alkylation, the dialkyl sulfates react much faster than do the alkyl haHdes, because the monoalkyl sulfate anion (ROSO ) is more effective as a leaving group than a haHde ion. The high rate is most apparent with small primary alkyl groups, eg, methyl and ethyl. Some leaving groups, such as the fluorinated sulfonate anion, eg, the triflate anion, CF SO, react even faster in ester form (4). Against phenoxide anion, the reaction rate is methyl triflate [333-27-7] dimethyl sulfate methyl toluenesulfonate [23373-38-8] (5). Dialkyl sulfates, as compared to alkyl chlorides, lack chloride ions in their products chloride corrodes and requires the use of a gas instead of a Hquid. The lower sulfates are much less expensive than lower bromides or iodides, and they also alkylate quickly. 

Primary alkyl group (Section 2.13) Structural unit of the type RCH2—, in which the point of attachment is to a primary carbon. 

What is an immediate precursor of j i-chloropropylbenzene " Because the two substituents have a meta relationship, the first substituent placed on the ring must be a meta director so that the second substitution will take place at the proper position. Furthermore, because primary alkyl groups such as propyl can t be introduced directly by Friedel-Crafts alkylation, the precursor of... 

An alkylation reaction is used to introduce a methyl or primary alkyl group onto the a position of a ketone, ester, or nitrile by S 2 reaction of an enolate ion with an alkyl halide. Thus, we need to look at the target molecule and identify any methyl or primary alkyl groups attached to an a carbon. In the present instance, the target has an a methyl group, which might be introduced by alkylation of an ester enolate ion with iodomethane. 

Complexes of the type RMn(CO)5, where R is a primary alkyl group, undergo facile CO insertion at room temperature. Carbonylated to the corresponding acyls have been the pentacarbonyls with R = Me 50, 69), Et 51, 70), n-Pr 51), and CHjSiMe, 243). The phenyl compound, PhMn(CO)j, also inserts CO, but the benzyl analog does not 51). The claim 194) that CX3Mn(CO)5 (X = H, D, or F) converts to CX3COMn-(CO) ( < 5) upon irradiation in an Ar matrix at 17°K has been disputed 209). Carbon monoxide dissociation and recombination have been proposed instead for MeMn(CO)5. 

Thermal insertion occurs at room temperature when R is XCH2CHAr-, at 40° C when R is benzyl, allyl, or crotyl (in this case two isomeric peroxides are formed), but not even at 80° C when R is a simple primary alkyl group. The insertion of O2 clearly involves prior dissociation of the Co—C bond to give more reactive species. The a-arylethyl complexes are known to decompose spontaneously into CoH and styrene derivatives (see Section B,l,f). Oxygen will presumably react with the hydride or Co(I) to give the hydroperoxide complex, which then adds to the styrene. The benzyl and allyl complexes appear to undergo homolytic fission to give Co(II) and free radicals (see Section B,l,a) in this case O2 would react first with the radicals. 

Amine (1) was needed to study the stereochemistry of alkylation reactions. The primary alkyl group had best come from an amide or an Imine while the secondary alkyl group must come from an imine. The disconnections may be carried out in any order. 

Trialkylstannyl chlorides undergo dealkylation in the presence of iodine chloride, as shown in reaction 27. The alkyl iodide product reacts further very slowly in the case of primary alkyl groups, however, reaction 28 proceeds readily for R = i -Pr. The mechanism involves a charge transfer complex that can be detected in the reaction mixture. The compounds involved in the process can be analysed by GC, NMR and UVV spectroscopy282. 

Primary amines RNH2, where R is a primary alkyl group such as Pr, benzyl or allyl, are oxidized to O-benzoylhydroxamic acids RNHOBz by benzoyl peroxide239. 

So far triptycenes carrying a secondary alkyl group in the 9-position have been found to give rather unstable atropisomers. To raise the barrier to rotation of the sec-alkyl group, the introduction of substituents in more than one peri position may be helpful the same is true when there is a primary alkyl group at the 9-position (vide infra). 

Structures such as (26) were demonstrated [103] to he fairly easily reduced at a Pt electrode. Thus, when R = Ph, an anion radical (E° = —1.26 V vs Ag/Agl/I 0.1 M) of high stahihty is formed. However, macroelectrolyses of the compounds (26) could not he achieved at all since whatever the amount of electricity passed through the cell, the starting material was totally recovered. The compounds (26) are expected to react slowly with the tetraalky-lammonium salt R4N+ and the reaction would correspond to an indirect reduction of the electrolyte. Compounds (26), with R = primary alkyl groups, led - even in DMF-to strong self-inhibition explained by the adsorption of produced... 

The method is suitable for the preparation of ethers having primary alkyl groups only. The alkyl group should be unhindered and the temperature be kept low. Otherwise the reaction favours the formation of alkene. The reaction follows S l pathway when the alcohol is secondary or tertiary about which you will learn in higher classes. However, the dehydration of secondary and tertiary alcohols to give corresponding ethers is unsuccessful as elimination competes over substitution and as a consequence, alkenes are easily formed. 

When secondary Grignard reagents are used, the coupling product sometimes is derived from the corresponding primary alkyl group.169 This transformation can occur by reversible formation of a nickel-alkene complex from the cr-bonded alkyl group. Reformation of the cr-bonded structure will be preferred at the less hindered primary position. 

With more substituted alkenes, reaction under these conditions is often accompanied by double-bond migrations which eventually lead to the formation of an alky ltrichloro silane with a primary alkyl group.51 52... 

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