( D , L )‐10‐Camphorsulfonic‐Acid‐Catalysed Synthesis of Diaryl‐Fused 2,8‐Dioxabicyclo[3.3.1]nonanes from 2‐Hydroxychalcones and Naphthol Derivatives

A tandem one‐pot Friedel–Crafts alkylation/double cyclization process to conveniently assemble diaryl‐fused 2,8‐dioxabicyclo[3.3.1]nonanes with aryl substituents at the C‐1 position was developed. 2‐Hydroxychalcones and naphthol derivatives reacted in refluxing toluene with ( D , L )‐10‐camphorsulfonic acid (CSA) as the catalyst. The transformation conveniently provided the corresponding 2,8‐dioxabicyclo[3.3.1]nonanes fused with one phenyl and one naphthyl group in moderate to good yields, and various substitutions on both reaction partners were tolerated. More importantly, aryl‐ and aza‐aryl‐fused 2,8‐dioxabicyclo[3.3.1]nonanes were prepared for the first time using this procedure.