Recent Development in Synthesis of N-Methylamines with Amines and Methanol

The N-methylation reaction of amines with methanol via the borrowing-hydrogen strategy is an important method for the construction of C-N bonds. Compared with other C1 sources, such as toxic formaldehyde or expensive formic acid, methanol is more suitable for N-methylation reactions due to its eco-friendliness and low price. Using this strategy, various types N-methylated products, including biological and pharmaceutical molecules have been prepared. Here, we present a thorough survey of decades of articles showing current developments in N-methylation reactions with methanol. We discuss homogenous, heterogenous and light-driven catalytic systems for both N-methylation and N,N-dimethylation reactions. This review presents the shortcomings of current developments and provides future development progress in N-methylation reactions with methanol. Carbon-Nitrogen bond formation plays a key role in the synthesis of functional organic intermediates. This review comprehensively summarized the N-methylation transformation of amine with methanol through the catalytic system of homogenous, heterogenous and photocatalyst, including that of mechanism study. Finally, the development direction of catalyst design for N-methylation was prospected. image