Convergent Synthesis of the Precursors to Thiophene-Based Quinoids.

A convergent (outside-to-center) route was adopted to synthesize the precursors of quinoidal compounds in high yields of 85-93%. With subsequent rearrangement/dehydroxylation and oxidation, a series of thiophene-based quinoids with indandione or oxindole terminal groups were successfully synthesized. This strategy shows good compatibility with versatile central and terminal units, leading to quinoidal compounds with tunable properties.