Reduction with TiCl3

Mechanism + Description

Mild and efficient reagent for nitro reduction. Mechanism is electron transfer followed by protonation.

General comments

Low valent Ti complexes can be used to reduce nitro groups to amines. The most common reagent is a solution of TiCl3. Ti2+ reagents usually need to be prepared in-situ using amalgams which gives rise to environmental issues. TiCl3 is available commercially. On quenching, metal oxide residues can be problematic.

 

Key references

Synthetic Commun. 1983, 13, 495  Selective Reduction of Nitro Compounds With Titanium (II) Reagents
Molecules 2005, 10, 1318  reduction of the nitro group of 5-nitroimidazoles with TiCl3

 

Relevant scale up example

Selective reduction with TiCl3  2 litre scale
Org. Process Res. Dev. 1999, 3, 347

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