Synthesis of Acridines and Persubstituted Phenols from Cyclobutenones and Active Methylene Ketones

A new benzannulation strategy that proceeds via a regiospecific [4 + 2] cycloaddition of readily available cyclobutenones and active methylene ketones has been developed. On the basis of this strategy, persubstituted phenols/anilines with up to six different functional groups on the benzene ring were synthesized in a single step. In addition, a series of acridine derivatives were prepared in excellent yield from persubstituted phenols/anilines.本研究开发了一种全新的苯环化（benzannulation）策略：该策略通过区域专一性[4 + 2]环加成反应，以易得的环丁烯酮（cyclobutenones）与活性亚甲基酮（active methylene ketones）为底物进行反应。基于该策略，可一步合成苯环上带有至多六种不同官能团的全取代苯酚/苯胺（persubstituted phenols/anilines）。此外，以该类全取代苯酚/苯胺为原料，可通过反应以优异收率制备一系列吖啶衍生物（acridine derivatives）。