In Quest of a Prismene. Organolithium-Induced Desulfonylation on Strained Hydrocarbons

Reaction of a twofold excess of n-butyllithium with 1,6-bis(tert-butylsulfonyl)tetracyclo[4.2.0.0^5,7]octane (14) yields a mixture of 3- and 5-n-butyl-2-(tert-butylsulfonyl)bicyclo[2.2.2]octa-2,5-dienes 15 and 16, respectively, while the reaction with 2,3-bis(tert-butylsulfonyl)quadricyclane (11) leads to 5-n-butyl-2-(tert-butylsulfonyl)bicyclo[2.2.1]hepta-2,6-diene (24), and the reaction with 2-(tert-butylsulfonyl)hexacyclo[9.5.0.0^1,3.0^2,10.0^3,9.0^9,11]hexadecane (8) yields a 1:1 mixture of 15-n-butyltetracyclo[7.5.2.0.0^2,8]hexadeca-2(8),15-diene (34) and 1-n-butyl-2,3:4,5-dipentanobenzene (35). Common to all three reactions is the elimination of tert-butylsulfinate and the addition of a butyllithium moiety. A radical mechanism is suggested rather than an elimination via a strained double bond incorporated in a strained cage system.