Stereospecific Addition of Dimethylsulfonium Methylide to 9,10-Anthraquinone

Abstract

Dispiro[2.2.2.2]deca-4,9-diene² (1) is a dispirocyclopropyl hydrocarbon with unusual chemical and structural properties. 1 undergoes facile and highly reversible thermal ring opening via two interconverting diradicals,³ one of which can be trapped in high yield with substituted butadienes thereby allowing entry into the [8]paracyclophane series.⁴ 1 has been shown by photoelectron spectroscopy to exhibit significant spiroconjugation.⁵ The cyclopropyl ring carbon-carbon bond lengths are of theoretical interest⁶ but have not yet been examined. We wish to explore these and other aspects of the chemistry and structure of a series of benzologues and oxyanalogues of 1 and now report the preparation and characterization of 2, a dioxybenzologue of 1.