The second leg was scheduled for 24 November and the kick-off was initially delayed after the bus carrying the Boca Juniors squad was attacked with pepper spray and stones on the way to River Plate's Monumental Stadium.
Several Boca players suffered cuts from broken glass and the effects of smoke inhalation. Conmebol, the organisers of the competition, eventually decided to postpone the clash.
An attempt to play the game on 25 November was also aborted.
Following a meeting between the presidents of the two clubs in the Paraguayan capital Asuncion, Conmebol said the game would be relocated to an as yet unspecified location.
A Conmebol statement said: "It would not be prudent to play the final in Argentina following the violence that put players, officials and fans at risk."
Following a 2-2 draw in the first leg at Boca's Bombanera stadium in Buenos Aires, the Boca president, Daniel Angelici, urged Conmebol to award his club the trophy following the attack.
Rodolfo D'Onofrio, his River Plate counterpart, condemned the demand as shameful.