Whoops -- you're right! I associated another actor from the same movie. Synapse lapse or not enough caffeine.
Here's another try:
3. Richard Dreyfus was in The Goodbye Girl with Marsha Mason.
This Michael Keaton one stalled, so I'll take it home...
4. Marsha Mason was in Max Dugan Returns with Jason Robards
5. Jason Robards was in The Paper with Michael Keaton