Encounter of an inferior intramolecular cyclization in an approach toward the synthesis of 10-oxo-2-thia[3.2]metacyclophane: Preparation of two isomeric dioxo-2,19-dithia[3.2.3.2]metacyclophanes

Abstract

The sodium sulfide coupling of 1,2-bis(3-bromomethyl)phenytethanone, Prepared in seven steps from m,α-dichlorotoluene, was attempted but failed to yield the. desired 10-oxo-2-thia[3,2]metacyclophane. This is, attributed to unfavoralle. geometry in the thiacyclophane, due to introduction of the sp2 carbonyl carbon. Two isomeric dioxo-dithia[3,2.3,2]metacyclophanes were however isolated from the coupling reaction. Both these cyclophanes were found to be conformationally highly mobile by variable-temperature NMR studies. © 1988.