An alternative synthetic route with better overall yield uses 1,4-benzoquinone and cyclohexa-1,3-diene as starting materials. 1,4-Benzoquinone (1) is first converted to 2,5-dibromo-1,4-benzoquinone (2), which reacts in a Diels–Alder reaction with cyclohexa-1,3-diene (3) to form the polycyclic diketone 4. This diketone photoisomerizes to 1,6-dibromopentacyclo[6.4.0.03,6.04,12.05,9]dodeca-2,7-dione (5), which undergoes a pseudo-Favorskii rearrangement in a 25% aqueous solution of sodium hydroxide, giving the dicarboxylic acid 6. The acid is decarboxylated with a modified Hunsdiecker reaction to a dibromide 7, which is reductively debrominated with tributyltin hydride to basketane (8) at a 11% yield relative to the starting material cyclohexa-1,3-diene.
