Preparation of 1,4-Naphthoquinones and 9,10-Anthraquinones through Brønsted Acid-Catalyzed 4+2 Cycloaddition

Key Points

• This research focuses on developing a robust synthetic method for 1,4-naphthoquinones and 9,10-anthraquinones through acid-catalyzed reactions.
• Brønsted acid-catalyzed [4+2] cycloaddition was used to synthesize substituted 1,4-NQs and 9,10-AQs.
• Reactions were performed under ambient conditions, with yields up to 90% for initial products.
• Dehydrogenation was employed to obtain the final quinone structures.
• 5,8-dihydro-1,4-NQs were synthesized in yields of up to 90%.
• The dehydrogenation resulted in 1,4-NQs with yields ranging from 62% to 98%.
• A second cycloaddition generated 1,4,5,8-tetrahydro-9,10-AQs with yields of 71% to 88%.