Quinazoline, Imidazoline, and Azetidine Heterocycles via Oxidative Sulfonamidation of Camphene

Abstract The NBS‐induced reaction of camphene with sulfonamides in acetonitrile in the presence of cesium carbonate and with three‐fold excess of NBS results in the formation of the Ritter type solvent interception products with spiro‐joined imidazoline ring and the unrearranged camphene framework (major products, up to 70 %), and the rearranged products with fused azetidine and camphene rings (minor products, up to 28 %). With equimolar amount of NBS, only the rearranged products of the quinazoline type with fused tetrahydropyrimidine and camphene rings are formed in up to 74 % yield. The azetidine derivatives of monoterpenes represent practically unknown class of compounds, their structure was proved by X‐ray analysis, and the mechanism of formation of all three types of products is discussed.