Synthesis of Alkyl- and Alkoxy-Substituted Benzils and Oxidative Coupling to Tetraalkoxyphenanthrene-9,10-diones

Article abstract of DOI:10.1021/jo00082a022

Intermolecular Friedel-Crafts acylation of various substituted alkyl- or alkoxybenzenes with oxalyl chloride using carbon disulfide as solvent gave rise to the benzils 1a-k.Subsequent intramolecular oxidative coupling with either thallium(III) oxide/trifluoroacetic acid or vanadium(V) oxyfluoride/boron trifluoride diethyl etherate resulted in the corresponding phenanthrene-9,10-diones 2a-d.It has been shown that oxygen functionalities at the 3,3',4, and 4'positions are necessary for coupling to occur.These substituted benzils and phenanthrene-9,10-diones constitute precursors for ligands in the field of discotic metallomesogens or polymeric mesogens.