Novel Cubane Derivatives obtained by Electron Transfer Nucleophilic Substitution Reactions

KARINA CRESPO; FEDERICO BRIGANTE; LILIANA B. JIMENEZ; ADRIANA B. PIERINI

Conferencia; 13th Latin American Conference on Physical Organic Chemistry; 2015

Cubane derivatives have been proposed as interesting building blocks for liquid crystals and, also, in nanostructures where the cubyl moiety acts as a rigid bridge for electron transfers between the acceptor and donor ending centers. Moreover, cubane derivatives are considered as biological stable lipophilic platforms on which it could be possible to use for controlled drug transportation and delivery if they are adequately substituted.The aim of this study is to obtain isolated novel cubane core compounds, using nucleophilic substitutions by electron transfer as methodology. The starting substrate is 1,4-diiodocubane and different sulfides and phosphide were used as nucleophiles. Also, the reaction mechanism is studied.NH3 and DMSO were used as solvents and the best yields for disubstituted products were obtained in NH3, ca. 50%. In the experimental conditions used, DMSO as solvent, ten times more concentrated than in NH3, a lower percentage of disubstituted compounds were obtained. However, in DMSO, it is found as a subproduct the monosubstituted compound with retention of the second leaving group, not observed in those photostimulated reactions done in NH3.When the reaction is performed in DMSO but under diluted conditions, same as NH3, monosubstituted compound with retention of the second leaving group is not observed. This result leads to deduce that intramolecular electron transfer is favored, resulting in a higher yield of dinucleophilic substitution product, and when the concentration of reactants increases, the intermolecular electron transfer becomes relevant over the intra electron transfer.In general, reactions carried out in NH3 have fewer byproducts, so the isolation process is simplified.