An Improved Procedure for the Conversion of Benzyl Halides into Benzaldehydes

Abstract

Oxidation of benzyl halides to benzaldehydes is an important synthetic reaction for which a number of procedures is available. Of these, the Sommelet¹ and Kröhnke^2–4 reactions are the most straightforward and commonly used, and while each has certain limitations, one or other can almost always be applied successfully to any given benzyl halide. Other procedures such as the Kornblum method^5,6 and oxidations with pyridine N-oxides,⁷ tertiary aliphatic amine N-oxides⁸ and the sodium salt of 2-nitropropane^9,10 have all been utilised with varying degrees of success, but these methods offer no significant advantage over the Sommelet or Kröhnke reactions in terms of manipulative simplicity, economy, or yields of pure aldehydes obtained.