Rearrangment–Cyclization of Dialkyl(4-hydroxybut-2-ynyl)(3-phenylprop-2-enyl)ammonium Bromides in the Presence of Aqueous Alkali

Dialkyl(4-hydroxybut-2-ynyl)(3-phenylprop-2-enyl)ammonium bromides in the presence of catalytic amounts of aqueous alkali do not undergo intramolecular [4+2]-cyclization of the diene synthesis type, because the 3-phenylprop-2-enyl group does not take part in the reaction as a diene fragment, and the initial salts are formed again. In the presence of a double amount of aqueous alkali, contrary to our expectations, the salts undergo Stevens rearrangement with transfer of the reaction center in both the host and migrating groups, followed by intramolecular cyclization rather than intramolecular cyclization–recyclization.