25. Condensation Chemistry

Which product is the most likely intramolecular aldol addition product formed when $O_2$-hexanedione is treated with base and then acid workup?

What is the major product formed when ${\mathrm{CH}}_2\mathrm{COCH}{2}_{\mathrm{CO}}\mathrm{CH}{2}_{\mathrm{CO}}\mathrm{CH}{2}_{\mathrm{CO}}\mathrm{CH}{2}_{\mathrm{CO}}\mathrm{CH}{2}_{\mathrm{CO}}$ (hexane-2,6-dione) undergoes intramolecular aldol condensation under basic conditions?

Consider the following reaction. Provide a stepwise mechanism to explain the given transformation.

Draw the product of the reaction of each of the following compounds with a base:

c.