Organic Letters 2013-09-20

Synthesis of fluorenone and anthraquinone derivatives from aryl- and aroyl-substituted propiolates.

Florian Pünner, Justin Schieven, Gerhard Hilt

Index: Org. Lett. 15(18) , 4888-91, (2013)

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Abstract

Fluorenone derivatives were generated from aryl-substituted propiolates via a cobalt-catalyzed Diels-Alder reaction/DDQ-oxidation and Friedel-Crafts-type cyclization. Several functional groups are tolerated, and good to excellent overall yields (up to 89%) could be achieved. For the synthesis of anthraquinone derivatives, aroyl-substituted propiolates were applied in a zinc iodide catalyzed Diels-Alder reaction with 1,3-dienes. The subsequent DDQ oxidation and Friedel-Crafts-type cyclization led to symmetrical as well as some unsymmetrical anthraquinones in good to excellent yields of up to 87% over the three-step reaction sequence.