Krdhnke oxidation

The method Is limited to activated halides which are stable to alkoxide bases and aqueous acids. According to the discoverer,the Krdhnke oxidation is inferior to the Sommelet reaction for benzyl halides, especially those bearing electron-withdrawing groups, such as nitro. Some representative examples are shown in Scheme (P and equations As can be seen, the Krdhnke oxidation is an... 

The Krdhnke oxidation often gives good results when other methods fail. In the example given (equation 13) neither the Sommelet or the Hass-Bender method gave any aldehyde. 

The Ortoleva-King-Krdhnke sequenee was frequently used to prepare multisubstituted pyridines. In fact, the acylpyridinium salt, obtained from the Ortoleva-King reaetion, was often referred to the Krdhnke salt . For example, a pyridine A-oxide based ehiral ligand 31 was synthesized by Maikov et a/." Prepared from 2-fIuoroacetophenone 27, Krohnke salt 28 underwent condensation with pinocarvone 29 and ammonium acetate, affording pyridine derivative 30. Further elaboration of 30 led to the... 

---