Telomerization to yield amines

These consecutive reactions can be avoided by using the biphasic method [10], which allows the selective production of the primary amines 4 and 5. The reaction takes place in an aqueous catalyst phase (Pd(OAc)2 + TPPTS) and the primary products are extracted in situ by a second organic phase (e.g., toluene, methylene chloride, butadiene) which is immiscible with water. 

By lowering the 7t-acceptor properties of the ligand, the activity of the catalyst system decreases [11]. 

The reductive amination of carbonyl compounds constitutes a convenient and practical approach to synthesizing primary amines and is generally performed by heterogeneous catalysts [12]. 

The hydroaminomethylation of 1-pentene and ammonia, with a Rh/Ir/TPPTS catalyst in an aqueous/organic two-phase system, was developed by BeUer et al. [14]. Under standard hydroformylation conditions (130°C, 12 MPa) amines could be isolated in 75% yield. By increasing the ammonia/olefin ratio and by using the extraction effect of the organic solvent as in Ref. [10], the selectivity for primary amines could reach more than 90%. This method could also be used for propene and 1-butene to give butylamine and pentylamine as main products. 

The synthesis of primary amines in biphasic operation has been developed via selective reductive amination of aromatic and aliphatic carbonyl compounds using aqueous ammonia in the presence of water-soluble transition metal catalysts [17]. The use of [Rh(cod)Cl]2 with TPPTS as catalyst and ammonium acetate in water/ THF afforded benzylamine from benzaldehyde in 86% yield. This method is also feasible for the synthesis of aliphatic primary amines from aliphatic aldehydes in 

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This section deals with catalyzed aminations in aqueous phases, so the developments discussed here must have some water in the reaction mixture. AH reactions known to synthesize amines via catalysts in the presence of water can be divided into four categories and are discussed in the following order Hartwig—Buchwald aminations, telomerization to yield amines, reductive aminations/hydroamino-methylations, and aUyhc aminations. 

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