Forster–Decker method

The Forster–Decker method is a series of chemical reactions that have the effect of mono-alkylating a primary amine (1), forming a secondary amine (6).^[1][2] The process occurs by way of transient formation of an imine (3) that undergoes the actual alkylation reaction.

The Forster-Decker method

Process stages

1. Conversion of the primary amine to an imine (Schiff base) using an aldehyde.^[3]
2. Alkylation of the imine using an alkyl halide, forming an iminium ion.^[4]
3. Hydrolysis of the iminium, releasing the secondary amine and regenerating the aldehyde. ^[5]

Because the actual alkylation occurs on the imine, over-alkylation is not possible. Therefore, this method does not suffer from side-reactions such as formation of tertiary amines as a simple S_N2-type process can.

See also

• Reductive amination