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 C source and silanes as reducing agents. This tandem process is efficiently accomplished in the presence of a cubane-type Mo PtS catalyst. For the preparation of the novel [Mo Pt(PPh )S Cl (dmen) ] (3 ) (dmen: N,N'-dimethylethylenediamine) compound we have followed a [3+1] building block strategy starting from the trinuclear [Mo S Cl (dmen) ] (1 ) and Pt(PPh ) (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.

Cubane‐Type [Mo3S4M] Clusters with First‐Row Groups 4–10 Transition‐Metal Halides Supported by C5Me5 Ligands on Molybdenum

“…Llusar, Pérez‐Prieto, and their co‐workers have synthesized diphosphine‐supported [Mo 3 S 4 Cu] clusters as catalysts for the intra‐ and intermolecular cyclopropanation of alkenes, whereas Llusar et al. have demonstrated the catalytic conversion of nitroarenes with a diamine‐supported [Mo 3 S 4 Pt] cluster . Therefore, the synthesis of various cubane‐type clusters with a potential reaction site should expand the utility of such metal‐sulfur compounds in bio‐inspired and homogeneous catalysis…”

“…[11] Llusar,P Ørez-Prieto, and their co-workers have synthesized diphosphine-supported [Mo 3 S 4 Cu] clusters as catalystsf or the intra-and intermolecular cyclopropanation of alkenes, [12] whereas Llusar et al have demonstrated the catalytic conversion of nitroarenes with ad iamine-supported [Mo 3 S 4 Pt] cluster. [13] Therefore, the synthesis of variousc ubane-type clustersw ith ap otentialr eaction site should expand the utility of such metal-sulfurc ompounds in bio-inspired and homogeneous catalysis. [14] Ap latform class that has already been employed in the synthesis of previously reported [Mo 3 S 4 M']( M ' = Groups 8-10 metals andG roup 6c arbonyls) clusters are cationic Mo 3 clusters of the type [(h 5 -C 5 H 4 Me) 3 Mo 3 S 4 ] + and [Cp* 3 Mo 3 S 4 ] + ([1] + ; Cp* = h 5 -C 5 Me 5 ).…”

Recent Advances in Methylation: A Guide for Selecting Methylation Reagents

“…Owing to the ease of synthesis of amines from the relevant organic nitro compounds, N,N‐dimethylated amines have been synthesized directly from nitro substrates by using FA as a renewable C 1 source and silanes as the reducing agents. The domino reaction (reduction/methylation) can be accomplished in the presence of a heterobimetallic cubane‐type Mo 3 PtS 4 catalyst . At room temperature, N‐heterocyclic arenes, double bonds, ketones, cyanides, and ester groups are well tolerated.…”

“…The domino reaction (reduction/methylation) can be accomplished in the presence of ah eterobimetallic cubane-type Mo 3 PtS 4 catalyst. [63] At room temperature, N-heterocyclic arenes, double bonds, ketones,c yanides, and ester groups are well tolerated. In addition, benzylic typea nd aliphatic nitro compoundsc an be methylated under the conditions.…”

Rhodium-catalyzed reductive carbonylation of aryl iodides to arylaldehydes with syngas

“…Ligands play a decisive role in adjusting the catalytic ability of metal cations [12,13,[41][42][43][44][45][46][47][48][49][50][51]. Different ligands coordinating with the same metal cations could make a difference between full conversion with nearly quantitative yields and no reactions.…”