Study of the behavior of p-bis{3-[N,N-dialkyl-N-(4-hydroxybut-2-ynyl)ammonio]prop-2-ynyl}-benzene dichlorides in relation to aqueous alkali. Double intramolecular recyclization of benzo[5,6;5′,6′-a,c]di(2,2-dialkyl-4-hydroxymethyl)isoindolinium dichlorides

Abstract

prop-2-ynyl}benzene dichlorides, dialkyl (6-dialkylaminomethyl-7,9,10,12-tetrahydro-8,11-dioxadicyclopenta[c,g]-phenanthren-1-ylmethyl)amines, base catalysis, double intramolecular cyclization, intramolecular recyclization. [3-dialkyl-2-propynylammonio-1-propynyl]benzene dibromides under base catalysis conditions undergo a double intramolecular cyclization of the diene synthesis type with the formation of benzo [5,6;5',6'-a,c]di(2,2-dialkylisoindolinium dibromides in almost quantitative yield [1]. NR 2 N NR 2 N + + Br -Br -R 2 OH -R 2 Br -Br -+ + __________________________________________________________________________________________ p-Bis

In Situ Allene Formation via Alkyne Tautomerization to Promote [4 + 2]-Cycloadditions with a Pendant Alkyne or Nitrile

“…In the case of 18-maj, these peaks showed a clear doublet (J = 8 Hz) for the H 12 C 13 CH coupling, whereas each leg of the analogous satellite resonance in 18-min was a singlet. The somewhat surprising preference for the formation of the angular rather than linear skeletal motif 12 stands in contrast with that often observed in classical electrophilic cyclizations, where steric factors imposed by a meta substituent often drive the preference (cf. intramolecular Friedel−Crafts, Bischer−Napieralski, or Nazarov reactions).…”