The Boekelheide Rearrangement of Pyrimidine<i>N</i>‐oxides as a Case Study of Closed or Open Shell Reactions ‐ Experimental and Computational Evidence for the Participation of Radical Intermediates
Heterocycles: The rearrangement of a model pyrimidine N-oxide with carboxylic acid anhydrides provides the acyloxymethyl-substituted compounds as major products. In addition, other compounds derived from radical intermediates are formed in considerable amounts under certain conditions. By comprehensive experimental and quantum-chemical calculations, a rationale for the apparently competing mechanisms is proposed