Synthesis of 2,2,4‐triphenyl‐3‐propenoyl‐3,4‐dihydro‐2H‐benzopyran via a lithiated allene

Synthetic routes to 2,2‐disubstituted chromanes and their hetero‐ring‐unsaturated analogues are briefly reviewed. A variety of common alkylating agents has been involved in such routes. Here, however, the alkylating agent is the lithiated form of 4‐tetrahydropyran‐2‐yloxybuta‐1‐2‐diene V. This reacted with benzophenone to give XIV. The synthesis of chromane XIV is here reported for the first time. The route to XIV is also both new and may prove versatile to other hetero‐ring‐substituted chromanes.