... Maybe this can help.

I only tried the following on an audio only clip, so probably the first thing to do is to detach the audio from video (Clip->Detach Audio) so as to have a separate audio clip to work on.

1. Select the audio clip in the timeline and make it into a storyline: Clip->Create Storyline.
2. Select the audio clip and copy (Cmd-C).
3. Place the playhead at the very start of the audio and do Edit->Paste as Connected Clip.

Now you have two copies of your audio, one connected to the other in a storyline.
The next step is to have each one to play only one of the channels.
Select each in turn, and in the Inspector, under Audio, go to Channel Configuration and choose "dual mono".
Select the top channel for one clip and the bottom channel for the other.

Now you have the two audio channels separated and can synchronize them - either manually or using the synchronize clip feature - but I guess that you know better than me how to do.