Boekelheide reaction

The Boekelheide reaction is a rearrangement of α-picoline-N-oxides to hydroxymethylpyridines.

[1] Originally the reaction was carried out using acetic anhydride, which typically required a period at reflux (~140 °C).

[2] The mechanism of the Boekelheide reaction begins by an acyl transfer from the trifluoroacetic anhydride to the N-oxide oxygen.

The α-methyl carbon is then deprotonated by the trifluoroacetate anion.

This sets the molecule up for a [3.3]-sigmatropic rearrangement which furnishes the trifluoroacetylated methylpyridine.