1. Activate the shutdown (Manage Jenkins->Prepare for Shutdown)
2. Update some plugins (Plugin Manager->Updates [tab] choose some plugins to be updated)
3. Click on Download now and install after restart
4. Cancel the shutdown some minutes later
5. Activate the shutdown again
6. Manage Jenkins->Manage plugins->Updates [tab]->Download now and install after restart
7. Checkbox Restart Jenkins when installation is complete and no jobs are running is pre-checked.

Notice that although the Checkbox Restart Jenkins when installation is complete and no jobs are running is pre-checked, if you click several times in the checkbox very quick the instance restart at the end.

Then, you cannot restart from there and needs as a workaround go to for example http://<JENKINS_URL>/restart