Nonreductive alkylation

Several nonreductive methods for cleavage of benzyl groups have also been developed. Treatment with s-butyllithium, followed by reaction with trimethyl borate and then hydrogen peroxide, liberates the alcohol.24 The lithiated ether forms an alkyl boronate, which is oxidized as discussed in Section 4.9.2. 

When the benzene-insoluble residue obtained at 200° C was subjected to nonreductive alkylation (33) the solubility was restored to 80%, and this strongly implies that the generation of new functional groups is responsible for the lower solubility at this temperature. However, in view of inter- or intramolecular alkylations that may accompany the cleavage reactions, it is not possible to correlate the extent of degradation with changes in the molecular weights. 

With the coal, reduction is not accompanied by formation of significant quantities of radical anions, and alkylation can occur by nonreductive paths. Furthermore, model studies of the reducing system reveal that the solvent tetrahydro-furan decomposes to yield ethylene and that appreciable quantities of hydride are generated. 

In model studies of the naphthalene-sodium-tetrahydro-furan system, tetrahydrofuran was found to decompose to ethylene and the sodium enolate of acetaldehyde, with the ethylene alkylating the naphthalene in both reductive and nonreductive modes. The initial step of this decomposition, proton abstraction from the alpha carbon of tetrahydrofuran, led to formation of a hydride of unknown form. 

Pyrolysis (Py), demineralization (DM), oxidation (Ox) (1-peroxyacetic acid), reductive and nonreductive alkylation (R), chemical (SiCl4-NaI), nitrogenation (N)(l ammoxidation, 2-urea). 

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