Cyclization of dialkyl(4-hydroxy-2-butynyl)-(3-isopropenylpropargyl)ammonium salts and intramolecular recyclization of the resultant products

2,2-Dialkyl(4-hydroxy-2-butynyl)(3-isopropenylpropargyl)ammonium chlorides in the presence of 0.2 molar equivalents of KOH in water undergo facile cyclization to give 2,2-dialkyl-4-hydroxymethyl-6-methylisoindolinium chlorides, which recyclize to dialkyl(6-methyl-1,3-dihydro-4-isobenzofuranylmethyl)amines by the action of a two-fold molar excess of KOH in water.