Photoinduced nucleophilic substitution of iodocubanes with arylthiolate and diphenylphosphanide ions. Experimental and computational approaches.

A new synthetic route to modify the cubane nucleus is reported here. Methyl-4-iodocubane-1-carboxylate (1) and 1,4-diiodocubane (2) were employed as reagents to react with arylthiolate and diphenylphosphanide ions under irradiation in liquid ammonia and dimethylsulphoxide. The reactions proceed to afford thioaryl- and diphenylphosphoryl- cubane derivatives in moderate to good yields.

Nucleophilic substitution of bromonorbornenes and derivatives by electron transfer reactions.

The photoinitiated substitution reactions of anti-7-bromobenzonorbornadiene (5), its syn isomer 6, exo-anti-13-bromobenzocyclobutanorbornene (7), syn-7-bromonorbornene (8) and bromonorbornane (9) with Me(3)Sn(-) and Ph(2)P(-) anions, in liquid ammonia, are here informed to occur with good yields of substitution. The stereochemical outcome is discussed in terms of calculations with the B3LYP functional and the 6-31+G* basis set; the solvent being included as a continuum through the PCM model. The experimental relative chemical reactivity of pairs of substrates toward a given anion is also presented.

Radical nucleophilic substitution of 2-(4-halophenyl)-2-methyl-1-chloropropane with enolate ions of ketones.

The photoinitiated reaction of 2-(4-halophenyl)-2-methyl-1-chloropropane 2a,b (halogen=Br, I, respectively) with the anions of pinacolone (3a) and acetophenone (3b) either in DMSO or in liquid ammonia are reported. In DMSO, the main reaction is the SRN1 nucleophilic substitution at the aromatic (Csp2-halogen) center with substitution or reduction at the aliphatic (Csp3-Cl) one. In liquid ammonia, the main reaction is substitution at the aromatic C-halogen site.