Transition Metal Ions as Efficient Catalysts for Facile Ortho-Formylation of Phenols under Vilsmeier–Haack Conditions

F Aneesa,M Arifuddin,K C Rajanna,Y Arun Kumar

doi:10.1155/2012/289023

Abstract

Aromatic compounds (phenols), when treated with Vilsmeier Haack (V-H) reagent in the presence of transition metal ions such as Cu(II), Ni(II), Co(II), Cd(II), and Zn(II) under reflux conditions, afforded corresponding ortho-formyl derivatives in good yields. Under normal conditions the metal-ion-free V-H reactions are too sluggish and resulted in poor yields. This protocol provides highly regioselective formylation under a mild and efficient condition with simple workup.

Highlights

One of the most fascinating developments seen in organic synthesis during the recent years is the application of transition metals for ortho functionalization of aromatic compound [1]
We have found that metal ions are good promoters for a variety of organic reactions such as Hunsdiecker reaction [23] and bromination reaction [24,25,26,27]
We report the selective formylation of phenols promoted by metal ions under Vilsmeier Haack (V-H) conditions

Summary

Introduction

One of the most fascinating developments seen in organic synthesis during the recent years is the application of transition metals for ortho functionalization of aromatic compound [1]. Ever since the application of transition metals in organic reactions is introduced, a number of chemical reactions have been reported to functionalize nonreactive aromatic C–H bond ortho to hydroxyl and other functional groups [2]. Formylation of aromatic compounds is a classical reaction in inorganic chemistry and numerous methods are available [3].

Results

Conclusion