Unfortunately, no. There's not much you can do about that right now as Facebook will follow those redirects. There is also no way to provide credentials to Facebook for them to 'see' your content.
We are investigating a way to prevent the redirection when we see that it's Facebook's crawler and instead just present a small HTML snippet with just the Open Graph tags. It's being investigated now, but there's a bit of difficulty getting it all working right to abide by Facebook's terms, work with Joomla's ACL, and other complications. That feature should be out later this year, but I can't give a better timeline.
The only options I would suggest are to use introtext in your articles and make the full text 'registration-required'. That way, Facebook (and users) can get a sneak peak of the article and Open Graph tags, but the full page won't be visible. That also has the benefit that user's can share even the introtext for your article, which may generate even more visibility.
I hope that helps explain and gives ideas. Should you have any questions or suggestions though, let us know,
Alex
Open Graph -Registered Site
