My wife doesn't have SSN/ITIN, Can I file for an extension as a single and then get the ITIN in time and finally file jointly later on?

So I got married in 2019, I am on H1B, my wife on H4, she was not qualified for SSN, I didn't have an idea about ITIN earlier. Coming back to the current situation with covid19 and lockdown. I can't get the ITIN timely. It will anyway take a long time. My question is can I file an extension as single and in due course get the ITIN and file jointly finally?