When you say "newly installed" do you mean there is nothing in there of yours, ie, just an empty clean database ?

If that's the case, why not just create a database using 11.2.0.1 ?

But in any event, I would suspect that your 'compatible' parameter might be at its default on 11.2.0.4 ? If so, then you can't downgrade, because the datafiles have been stamped as 11.2.0.4.

If compatible is 11.2.0.1, then you could run the downgrade scripts as per the upgrade guide.

If you just want the optimizer to work as if it was in 11.2.0.1, I'd just set optimizer_features_enabled appropriately and leave it at 11.2.0.4

Hope this helps.