Bis(phenylsulfonyl)alkenes: from enantiopure ketones to fullerene substructures

The synthetic potential of bis(phenylsulfonyl)alkenes, especially in view o f their ability to function as equivalents of acetylene in cycloaddition re actions for the preparation of polycyclic molecules, is discussed. Differen tly from the bis(phenylsulfonyl)alkenes, bis(phenylsulfonyl)-acetylene has to be prepared and reacted in situ and affords polycyclic bis(phenylsulfony l)aIkenes upon Diels-Alder reaction. The same products arising from bis(phe nylsulfonyl)acetylene can be more products arising from bis(phenylsulfonyl) acetylene can be more conveniently prepared by cycloaddition of (E)-1-chlor o-1,2-bis(phenylsulfonyl)ethylene and dehydrochlorination with triethylamin e. They react with enantiopure Ce-symmetric diols with complete enantiotopi c discrimination, eventually leading to polycyclic enantiopure ketones of k nown configuration. The enantiopure ketones, transformed into bromoalkenes, are further transformed into bromotrimethylstannyl alkenes. Upon treatment with copper nitrate trihydrated, the latter undergo cyclotrimerisation to benzotrisnorbornadienes in high yield. These molecules are composed of five and six membered rings as the fullerenes and can function as host compound s, as a kind of calixarene. The rearrangements eventually leading to fuller enes substructures and fullerene C-60 itself will be discussed.