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

Abstract

Reaction of a twofold excess of n-butyllithium with 1,6-bis(tert-butylsulfonyl)tetracyclo[4.2.0.05,7]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[9.5.0.01,3.02,10.03,9.09,11]hexadecane (8) yields a 1:1 mixture of 15-n-butyltetracyclo[7.5.2.0.02,8]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.

Organic molecules with abnormal geometric parameters

“…The attempts to synthesise derivatives with even more pyramidalised carbon atoms of the C=C bond, prismene, have so far been unsuccessful. 248 Both prismene isomers, 130 and 131, have been studied theoretically [HF/6-31G(d), MP2/6-31G(d)]. 249 According to calculations, the energy of the molecule 131 is lower than the energy of 130.…”

Dehydroquadricyclanes

“…In nearly all cases of this study, anionic leaving groups were halides. Gleiter has shown recently that completely different mechanisms are operative if quadricyclyl sulfones are treated with organolithium bases [24]. In this case, SET processes were involved which lead to fast ring opening of the quadricyclyl framework circumventing the formation of dehydroquadricyclanes.…”

“…23 24 of its adducts seems necessary. b) 1,7-Dehydroquadricyclane 3 and 2,5dimethylfuran and 1,2,3-trimethylisoindole could lead to two adducts of type 23 and 24, as depicted for the isoindole case.…”