Galatians 2 absolutely refers to the council of acts 15. One of my professors raised the question on Facebook today, and I found myself typing quickly:
It's been twelve years since I did the research, but I don't recall anyone who argues for this; at least, not anyone who argues particularly well. My own reconstruction comes together by starting with the "men from James".
Assuming the Judaizers in Galatia were almost certainly the same men who caused trouble in Antioch - because when & where else, before the council, could they have heard about churches in Galatia?! - we must reconstruct their itinerary in parallel against Paul's itinerary. So, if these men who prompted the trouble in Antioch which sparked the council in Jerusalem LEFT Antioch and went into Galatia, then it is far more likely that Paul and Barnabas were traveling to and from the council around the same time the Judaizers were traveling to and from Galatia. In that case, Paul & Barnabas visit Jerusalem, do the council, return home, split up, and THEN Paul gets word about Galatia, and then he (alone) writes the letter.
Otherwise, you'd have to suppose several unlikely scenarios, each in turn: Paul (1) waits around in Antioch (WITH Barnabas) ignoring the problem with Jerusalem... ignoring it for at least a year...for so long that the whole Galatians problem has enough time to develop, boil over, and have word get back to Paul; (2) Paul then writes Galatians (WITHOUT Barnabas, who is also there) and Paul sends it to them without being able to follow up soon in person; (3) Paul next travels down to Jerusalem (WITH Barnabas), submitting himself to the people he's just written about so resentfully (as opposed to submitting to them and *then* writing about them resentfully!); (4) Paul finally returns home to Antioch, and incidentally splits up with Barnabas, who didn't want to visit Galatia, even though he should know by now that Galatia needs help recovering from a festering crisis; (5) And only THEN, after all that, Paul finally says, yep, I better go visit these relatively new believers who are desperate for help and have nobody but me to rely on! That's implausible in the extreme.
The traditional argument for the consensus is that Galatians doesn't mention Acts 15 - in particular, Jerusalem's letter - but I like to point out Paul didn't share Jerusalem's letter with Corinth, either. That's why Peter's visit to Corinth raised so many questions about those three rules, which Paul then had to answer in 1Cor. If Paul didn't mention those three rules during 18 months living with the Corinthians, there's no reason to expect he should mention them during a single letter to the Galatians.
Also, there is Titus.
(This is less weighty, but it's my favorite part!)
Because Paul assumes the Galatians know who Titus is, it seems obvious that Titus must be the letter carrier. But because it's unlikely Titus would have gone alone, he probably went with a partner. If we suppose that partner was probably Luke, it would explain how and why Paul finds Luke in Troas - the same town Titus seems to frequent in later years, and the only church in Acts whose origin Luke doesn't explain. To me, it looks like Titus and Luke carried the Galatian letter and then proceeded to an agreed upon rendezvous at "Troy" (as the most famous location west of Galatia they could be sure to remember correctly, and ask about, it was a perfect rendezvous point for inexperienced travelers from Antioch). The point, here, is that the explanatory power of all this vanishes completely if Paul sends the Galatian letter with no immediate follow-up plans. This can't happen if Luke & Titus are waiting in Troy indefinitely, because Paul (WITH Barnabas) is waiting on the Jerusalem council.
And besides all that... Paul didn't need to write about the council because Titus had been there with Paul. If you want, you can easily suppose Titus carried the letter from Jerusalem along with Paul's letter. It would have been wise to keep that in reserve, and save it after reading Paul's letter, if at all.
On balance, there should be no question that Gal.2 = Acts 15.
Someday in the far future I will hopefully publish on this. In the meantime, dear readers, please share this post far and wide.
I'd seriously love to find a co-author to help me develop this argument for publication.