The Lotus Notes platform cannot sync to Google Calendar.
LNGoogleCalSync is a free, open-source solution. It’s a small Java application that will allow you to specify your Lotus Notes details, along with your Google Calendar details, and update any new meetings or appointments from your Lotus Notes calendar to Google Calendar.
Notifications can be transferred as Reminders in Google Calendar, and then also synchronized to a multitude of mobile devices such as iPhones and Android devices.
Regular synchronization of this application is also easy. Running the program with the ‘-silent’ parameter, will hide any GUI prompts. Task Scheduler can be used in Windows XP, Vista and 7, to allow for regular synchronization updates.
The main website seems to be slightly out of date, in terms of information, however the download link will still provide you with the latest version from the Source Forge project page.