A Different Behaviour of the Phthalimide Ion in Srn1 Reactions

The phthalimide anion reacts by the SRN1 mechanism under photostimulation with different substrates. Whilst with 1-iodonaphthalene only reduction of the naphthyl radical is observed, with 1-iodoadamantane coupling at the carbon instead of at the nitrogen takes place. Introduction The mechanism of Radical Nucleophilic Substitution (SRN1) is a chain process with radicals and radical anions as intermediates [1]. Different substrates and nucleophiles participate in these reactions. It is known that within the nitrogen-centered nucleophiles, aromatic amines react with aryl halides to yield the substitution product on the carbon atom and none on the nitrogen atom. For example, the photoinduced reaction of 2-naphthylamine with aryl halides renders mainly 1-aryl-2-naphthylamines [2]. However, the phthalimide ion (1) reacts with ter-butyl radicals yielding N-ter-butylphthalimide (2) (eq.1) [3]. Taking into account these results we began to study the photoinduced reactions of phthalimide ion with different substrates. Results and Discussion The photoinduced reaction of anion 1 with 1-iodonaphthalene (3) in dimethylsulfoxide (DMSO) and in the presence of 18-crown-ether renders 72% of iodide ions after three hours and naphthalene is the only product observed. This reaction does not occur in the dark. The reaction of anion 1 with 1-iodoadamantane (4) under the same conditions, yields a 78% of iohν, DMSO (1) SRN1 N O O + t-BuHgCl N-Bu-t O