Under the action of a twofold excess of KOH and heating in aqueous solution, and also under the conditions of the Stevens rearrangement (with KOH powder and a small amount of methanol) dialkyl-(4-hydroxy-2-butynyl)(3-phenylallyl) ammonium bromides form dialkyl [4- (1-phenylallyl)-2, 5-dihydro-2-furyl] amines. Rearrangement–cleavage reaction also occurs under the same conditions.