Efficient and Selective N‐Methylation of Nitroarenes under Mild Reaction Conditions

Abstract

Herein, we report a straightforward protocol for the preparation of N,N‐dimethylated amines from readily available nitro starting materials using formic acid as a renewable C1 source and silanes as reducing agents. This tandem process is efficiently accomplished in the presence of a cubane‐type Mo3PtS4 catalyst. For the preparation of the novel [Mo3Pt(PPh3)S4Cl3(dmen)3]+ (3+) (dmen: N,N′‐dimethylethylenediamine) compound we have followed a [3+1] building block strategy starting from the trinuclear [Mo3S4Cl3(dmen)3]+ (1+) and Pt(PPh3)4 (2) complexes. The heterobimetallic 3+ cation preserves the main structural features of its 1+ cluster precursor. Interestingly, this catalytic protocol operates at room temperature with high chemoselectivity when the 3+ catalyst co‐exists with its trinuclear 1+ precursor. N‐heterocyclic arenes, double bonds, ketones, cyanides and ester functional groups are well retained after N‐methylation of the corresponding functionalized nitroarenes. In addition, benzylic‐type as well as aliphatic nitro compounds can also be methylated following this protocol.