Base catalyzed intramolecular cycloaddition of dialkyl(4-hydroxybutyn-2-yl)[3-(p-tolyl)propyn-2-yl]ammonium chlorides and intramolecular recyclization of the products obtained
Dialkyl(4-hydroxybutyn-2-yl)[3-(p-tolyl)propyn-2-yl]ammonium chlorides undergo a diene synthesis type intramolecular cyclization in aqueous base medium to give 2,2-dialkyl-4-hydroxymethyl-6-methyl-benzo[f]isoindolinium chlorides. Under conditions of aqueous base fission intramolecular cyclization of the latter gives 4-dialkylaminomethyl-8-methyl-1,3-dihydronaphtho[1,2-c]furans.