F-Alkyl iodides

Tertiary nitroalkanes, on the other hand, are converted by ISi(CH3)3 (2 equiv.) into the f-alkyl iodides in high yield. 

Vismara, E., Fontana, F., Minisci, F. Alkyl iodides as source of alkyl radicals, useful for selective syntheses. NATOASI Ser., Sen C1989, 260, 53-69. 

Brown and McDonald (1966) provided another type of kinetic evidence for these size relationships by determining secondary kinetic isotope effects in reactions of pyridine-4-pyridines with alkyl iodides. For example, the isotopic rate ratio in the reaction between 4-(methyl-d3)-pyridine and methyl iodide at 25-0 C in nitrobenzene solution was determined to be kjyfk = l-OOl, while that in the corresponding reaction with 2,6-(dimethyl-d6)-pyridine was 1-095. (Brown and McDonald (1966) estimate an uncertainty of 1% in the k jk values.) Furthermore, the isotopic rate ratio in the case of the 2-(methyl-d3)-compound increased from 1 030 to 1-073 as the alkyl group in the alkyl iodide was changed from methyl to isopropyl, i.e. the isotope effect increased with increasing steric requirements of the alkyl iodide. 

Long-chain alkyl iodides. F.vcn-numbcred alkyl compounds of chain lengths up to 42 carbon atoms can be prepared by metathesis of I-alkenes with WC14-Sn(OH i)4, originally used for metathesis of unsaluratcd fatty esters to alkenes and... 

AgOTf, 2,6-di-f-butylpyridine 1° alkyl iodide, PhCH2Cl, H2C=CHCH2Br TL 35 8111 (1994)... 

Br —4, and 1+16 kcal mole-1)119 reflect the decreasing bond dissociation energies for H—X and C—X bonds in the series F, Cl, Br, I, and the relatively constant Z)(X—X) (Table 9.4). The highly exothermic fluorination requires no external initiators and occurs violently and uncontrollably on mixing fluorine with a hydrocarbon either in the gas or liquid phase. Chlorination must be initiated, but proceeds readily, whereas bromination frequently requires elevated temperatures. Iodination is rarely successful, and indeed is more likely to occur in the reverse direction as reduction of alkyl iodides by HI.120... 

Alkylation of cyclopropanecarboxylic acid esters,6 Deprotonation of methyl silyloxycyclopropanecarboxylates (1), prepared as shown, is possible with LDA in THF at — 78°. The resulting anions react with primary alkyl iodides and benzylic or allylic bromides to give 2 in high yield. These products are cleaved by F to methyl 4-ketocarboxylates 3. 

Treating 3-acetoxy-2-methyl-4/f-pyrido[l,2-sodium hydrogen carbonate in methanol at 60°C for 4 hours, then at ambient temperature for 16 hours, gave 3-hydroxypyridopyrimidine-7-carboxylate 416 (84FES837). The free hydroxyl group of compound 416 was alkylated with an alkyl iodide in dimethylformamide in the presence of potassium carbonate at room temperature or with 2-methoxyethoxymethyl chloride in dichloromethane in the presence of diisopropylethylamine at ambient temperature for 3 hours to give 3-alkoxy derivatives 417. 

Bailey, W. F. Brubaker, J. D. Jordan, K. P. Effect of solvent and temperature on the lithium-iodine exchange of primary alkyl iodides reaction of tBuLi with 1-iodooctane in heptane-ether mixtures./. Organomet. Chem. 

The initially formed radical R disproportionates (path a),dimerizes (path b), reacts with active cathodes (path c), rearranges (path d), adds to double bonds (path e) or is reduced to an anion (path f). Products of radical origin (a—e) occur mainly in the reduction of alkyl iodides, benzyl halides and in some cases of alkyl bromides. 

Primary alkyl iodides reacting via a polar mechanism, at least with f-BuLi in Et20-pentane mixtures... 

Halosilanes are also potent halogen donors, particularly in exchange reactions with alkyl fluorides, due to the strong Si-F bond formation. Tertiary- and secondary-alkyl fluorides are reacted with iodotrimethylsilane to yield alkyl iodides in high yields (equation 19)214 ... 

A series of tricyanomethyl compounds were prepared in refluxing acetonitrile hy alkylating potassium tricyanometha-nide with alkyl iodides, allyl, propargyl, and benzyl bromides. Yields of 20-57% were obtained for mono- and difunctional halides with a reflux time of 72 hours. The heats of combustion of these tricyanomethyl compounds as well as of two polycyano compounds were measured using a Dickenson-type calorimeter, and heats of formation were calculated with a precision of approximately 1.0%. From Pitzers values for C—C and C—H bond energies, that of the tricyanomethyl moiety is calculated to be about 810 kcal./mole, and the tricyanomethyl group is less stable than expected from comparison with AH°f of propylcyanide. 

Diem et al. investigated the photolysis of adamantyl iodide as a po ible source of carbocationic initiation for the polymerisation of isobutene. Althou no polymer was obtained with this simple tystem (or with f-butyl iodide as photolyte), addition of iodine scavengers such as zinc, zinc fodide or both together gave some polymerisation, indicating that the carbocations produced in the photolysis of alkyl iodides possess a modest initiating power if generated in the presence of isobutene. 

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