Yes, this is achievable and all you'd need to do is create a CNAME record in your .com admin console to point to your DDNS domain name.
I've never tried it but I wonder if you may have bproblems where typing your .com address may redirect to your ddns domain name in the browser.
Alternatively, to ensure your domain name remains the same in the browser you could create an A Record to point your www.example.com domain name to your ISp public IP. The only downside of this is if your IP changes you'll need to change it in your .com domain name registrar control panel each time so that it correctly points to your latest IP.
See the answer here: https://serverfault.com/questions/65712/using-cname-to-point-to-another-domain-to-save-ip-addresses
Finally: Could you ask your ISP if they can provide you a static or sticky IP?