Hydrogen transfer alkylamines

Nuclear and side chain substitution in aromatics or substitution of a -hydrogen in alkylamines is — in most cases — best rationalized by postulating radical cations as intermediates. For anodic nuclear substitution of aromatics, especially for acyloxylation, cyanation or bromination a ECnECb3 -mechanism is assumed 37,4 9,50,226,227). jc-oxidation of the aromatic to the radical cation 28, which reacts with a nucleophile Nu, e.g., acetate, cyanide, alkoxide, followed by a second electron transfer and deprotonation (Eq. (98) ) ... 

Most hydrogen transfers and other isomerizations of ionized alkylamines generally occur via DIs rather than DSfCs. However, the participation of an INC in DHT remains an attractive proposition, even if it occurs after the first hydrogen transfer has taken place to give a DI. DHT involving an intact N-alkyl chain and eventual C—N cleavage may also occur via isomerization to a S-DI, with production of an ammonium (or aUcylammonium) cation. ... 

The following sequence (equation 6) constitutes a convenient alternative to the conversion of alkyl halides into alkylamines by the Gabriel reaction with potassium phthaUmide. In this one-pot procedure, an alkyl bromide RBr (R = Bu, -Bu, 2-pentyl, 2-octyl, PhCH2CH2, HC=C, PhCH=CHCH2, cyclopentyl, cyclohexyl etc.) is treated with sodium azide in benzene in the presence of tetrabutylammonium bromide under phase-transfer conditions. Triethyl phosphite is then added and the resulting iminophosphorane is decomposed to the alkyl amine hydrochloride by adding benzene and hydrogen chloride. ... 

A significant limitation in both of these attractive protocols is the requirement of stoichiometric quantities of the Hantzsch ester for the transfer hydrogenation step. Recently, Seller [318] disclosed a strategy that uses a chiral phosphoric acid in combination with Knolker s iron complex (77) and hydrogen gas to complete the reduction with good enantioselectivity (up to 94% ee) (Scheme 15.96). Because Au is used for the alkyne hydroamination step, the Markovnikov product is selectively obtained. While a variety of arylamines can be used in combination with either aryl- or alkylalkynes, alkylamine substrates continue to present a challenge [319]. 

As the long-chain alkylamines meant here in general derive from fatty acids, they are also termed fatty amines, or more correctly fatty C8-C22 alkylamines. A processing technic is the catalytic dehydration of fatty alcohols at 210-260°C with ammonia or shortchain alkylamines or dialkylamines. Another manufacturing process starts from fats or oils which are transferred to fatty acid amides with ammonia dehydration of the amides leads to nitriles the catalytic hydrogenation of which produces fatty amines ... 

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