π‐Stacked dimers in 6‐methoxy‐3,3‐dimethyl‐3H‐benzo[f]chromene,and centrosymmetric dimers containing C—H...π(arene) hydrogen bonds in racemic 3‐bromo‐2,2,6,6‐tetramethyl‐3,4‐dihydro‐2H,6H‐1,5‐dioxatriphenylene

The title compounds, namely 6‐methoxy‐3,3‐dimethyl‐3H‐benzo[f]chromene, C₁₆H₁₆O₂, (III), and racemic 3‐bromo‐2,2,6,6‐tetramethyl‐3,4‐dihydro‐2H,6H‐1,5‐dioxatriphenylene, C₂₀H₂₁BrO₂, (IV), were both synthesized in one‐step regioselective Wittig reactions from substituted 1,2‐naphthoquinones. The new ring in both compounds adopts a screw‐boat conformation. A single π–π stacking interaction links the molecules of (III) into centrosymmetric dimeric aggregates, and a single C—H...π(arene) hydrogen bond links the molecules of (IV) into centrosymmetric dimers.