Vilsmeier-Haack Reaction

• General Characteristics

The Vilsmeier-Haack reaction is a common method to introduce a formyl group into electron rich aromatic compounds. It is also applicable to electron rich alkenes. The procedure is simple and the reaction conditions are not particularly harsh either.

• General References

・Vilsmeier, A.; Haack, A. Ber. 1927, 60, 119.
・Jackson, W. G. et al. J. Am. Chem. Soc. 1991, 103, 533. DOI: 10.1021/ja00393a008
・Meth-Cohn, O, Comprehensive Organic Synthesis 1991, 2, 777.
・Jones, G. Org. React. 2000, 56, 355.

• Reaction Mechanism

DMF and phosphorus oxychloride react to form the Vilsmeier reagent, which undergoes S_EAr reaction. Hydrolysis of the iminium intermediate gives the formylated product.

• Examples

A reaction example.^[1]

An example employing DMF-Tf₂O.^[2]

• Experimental Procedure

• Experimental Tips

• References

[1]
[2] Martinez, A. G.; Alvarez, R. M.; Barcina, J. O.; Cereo, S. M.; Vilar, E. T.; Fraile, A. G.; Hanack, M.; Subramanian, L. R. J. Chem. Soc., Chem. Commun. 1990, 1571.

• Related Books

 

electrophilic aromatic substitution, formylation