Bis(Phenylsulfonyl)Alkenes: From Enantiopure Ketones to Fullerene Substructures

Abstract

The synthetic potential of bis(phenylsulfonyl)alkenes, especially in view of their ability to function as equivalents of acetylene in cycloaddition reactions for the preparation of polycyclic molecules, is discussed. Differently from the bis(phenylsulfonyl)alkenes, bis(phenylsulfonyl)-acetylene has to be prepared and reacted in situ and affords polycyclic bis(phenylsulfonyl)alkenes upon Diels-Alder reaction. The same products arising from bis(phenylsulfonyl)acetylene can be more products arising from bis(phenylsulfonyl)acetylene can be more conveniently prepared by cycloaddition of (E)-1-chloro-1,2-bis(phenylsulfonyl)ethylene and dehydrochlorination with triethylamine. They react with enantiopure C2-symmetric diols with complete enantiotopic discrimination, eventually leading to polycyclic enantiopure ketones of known configuration. The enantiopure ketones, transformed into bromoalkenes, are further transformed into bromotrimethylstannyl alkenes. Upon treatment with copper nitrate trihydrated, the latter undergo cyclotrimerisation to benzotrisnorbomadienes in high yield. These molecules are composed of five and six membered rings as the fullerenes and can function as host compounds, as a kind of calixarene. The rearrangements eventually leading to fullerenes substructures and fullerene C60 itself will be discussed.