Behavior of propargyl- and allylpropargyl-ammonium salts in aqueous alkaline medium. Synthesis of 2-methyl-2-phenylbenz[f]isoindolinium and 2-methyl-2-phenylisoindolinium salts

Abstract

Methylphenylpropargyl-(3-phenylpropargyl)-ammonium bromide salts are cyclized almost quantitatively under base-catalysis conditions with the formation of 2-methyl-2-phenylbenz[f]isoindolinium bromide. The allyl analog is subject to rearrangement-decomposition, to a Stevens rearrangement, and to nucleophilic substitution, the cyclic product being obtained in low yield. Methylphenylpropargyl-(3-vinylpropargyl)ammonium bromide is mainly cyclized, but the 3-isopropenylpropargyl analog of this salt is subject to cyclization and subsequent decomposition under analogous conditions.