Reactions of 9-Phenylthioxanthene 10-Oxide with Organometallic Reagents

Abstract

Reaction of 9-phenylthioxanthene 10-oxide (1) with a variety of Grignard reagents afforded 9-substituted 9-phenylthioxanthenes (2). Similarly, organolithiums reacted with the sulfoxide 1 to give the corresponding thioxanthenes 2. The structures of 9-aryl-9-phenylthioxanthenes (2d-i) were confirmed by the alternative synthesis of the samples via the acid-catalyzed cyclization of triarylmethanol derivatives 5. A possible mechanism by way of a 9-phenylthioxanthylium ion intermediate is proposed for the reaction of the sulfoxide 1 with organometallic reagents.