Oracle alternative edition for Windows Server 2012
You'll find that information the the Oracle reference document 1307195.1: Certification Information for Oracle Database on Microsoft Windows x64 (64-bit). 

The latest Windows server version where 11.2 is supported is Windows 2008R2. Oracle 12c (12.1) is supported on Windows 2012 (including Hyper-V guests), but only in single instance mode (no RAC).

You can also find that information in the install guides, e.g.:


11.2 install guide, software requirements - Windows 2012 not listed
12.1 install guide, software requirements - Four editions of Windows 2012 x64 listed (note that the Server Core edition is not supported).