Synthesis of 3-aryl-1,4-benzoxathianes: application to the preparation of a sweet compound

Attempts to prepare 3-phenyl-1,4-benzoxathiane by acid-catalysed ring-closure of 2-(2-hydroxyphenylthio)-2-phenylethanol gave instead 2-phenyl-1,4- benzoxathiane, via a rearrangement probably involving an episulfonium ion. The first synthesis of 3-aryl-1,4-benzoxathianes was obtained by N-bromosuccinimide-promoted oxidative rearrangement of 1,3-oxathiolanes derived from cyclohexanone. The application of this route to the synthesis of 3-(3-hydroxy-4-methoxyphenyl)-1,4-benzoxathiane, a compound ca. 2000 times as sweet as sucrose, is reported.