( 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.