Aniline, formation Benzyl alcohol

Polyelectrolytes and soluble polymers containing triarylamine monomers have been applied successfully for the indirect electrochemical oxidation of benzylic alcohols to the benzaldehydes. With the triarylamine polyelectrolyte systems, no additional supporting electrolyte was necessary [91]. Polymer-coated electrodes containing triarylamine redox centers have also been generated either by coating of the electrode with poly(4-vinyltri-arylamine) films [92], or by electrochemical polymerization of 4-vinyl- or 4-(l-hydroxy-ethyl) triarylamines [93], or pyrrol- or aniline-linked triarylamines [94], Triarylamine radical cations are also suitable to induce pericyclic reactions via olefin radical cations in the form of an electron-transfer chain reaction. These include radical cation cycloadditions [95], dioxetane [96] and endoperoxide formation [97], and cycloreversion reactions [98]. 

The hydrolysis of benzylphenylamine [15, 16] was investigated in a batch autoclave at 385 °C in the pressure range of 22 to 100 MPa, and was found to lead to the formation of aniline, benzyl alcohol and toluene as the main products. The selectivity towards hydrolysis is increased at higher pressure and in the presence of NaCl. The hydrolysis of nitriles to amides and further to alcohols has been investigated mainly at subcritical conditions in batch reactors (Scheme 14.1). 

After discovering the catalytic activity of aldehydes, Xu and co-workers later extended the method to TM-free aldehyde-catalyzed C-alkylation of secondary alcohols with primary alcohols [199] and catalyst-free C-alkylation reactions of methyl ketones with alcohols [200]. In 2013, Wu and co-workers also reported a closely related TM-free ketone-initiated C-alkylation of indole and pyrrole with secondary alcohols [201]. Similarly, Shi and co-workers employed conjugated ketones to catalyze the TM-free A/-alkylation reaction of amines with alcohols in 2015 (Scheme 42) [202], which is mainly suitable for benzylic and heterobenzylic alcohols, and anilines and heteroarylamines. Different ketones showed variant activities in the reaction (the catalysts were added in the same amount of 50 mg regardless of their molecular weights). In mechanistic studies such as the control reactions of the ketone catalyst and the substrate alcohol, up to 92 % ratio of the corresponding alcohol derived from reduction of the ketone catalyst can be detected in addition to formation of aldehdye intermediates derived from substrate alcohol. 

In 2015, Yao, Zhao, and co-workers reported a base-catalyzed IV-alkylation of anilines and heteroarylamines with benzylic, heterobenzylic, aliphatic alcohols using catalytic amounts of O2 as the initiator (Eq. 69) [208]. They found air or O2 play important roles in the reactions because the reactions under O2 or in open air led to formation of imines in high ratios. The authors further optimized the reaction conditions and found that adding 2-5 mol% O2 to the reaction vessel was the best, giving high yields and selectivies of the product amines. Therefore, they proposed a mechanism for the N-alkylation reaction that was initiated by base-catalyzed aerobic alcohol oxidation by O2 to the aldehydes (Scheme 48). 

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