Not directly. Just awkward workarounds, like:

1. Eyedropper: Click the path you want to trim, to set current stroke/fill to match.

2. Turn on SmartGuides to get a reliable snap.

2. Ellipse Tool: mousedown on the corner point you want to round, drag out the ellipse.

4. Select both paths. Click the Divide Pathfinder.

5. Delete the now-separate path of the corner.

6. Select the two paths. AltClick the Add Pathfinder.

Or, do a search in this and the AI Mac forums. Someone has an Action or script to semi-automate this.

JET