Thank you for your comments. I tried to implement this suggestion. However, alerts are not getting triggered and am unsure as to what the missing piece is. I am attaching my workpoint setup (Alert.zip) just in case if that helps to figure out what i'm missing.
I enabled the logging to make sure that when a request is submitted, it does capture the timeout condition and uses that to trigger the alert. In the example setup, am trying to trigger the email alert after 15 minutes once the request is opened. The logs however does not show any sort of event that triggered an alert regarding the pending work item for approval.
Also, is there any way I can differentiate the requests that were rejected by a person and those that got automatically timed out.