I just updated an mvc4 project (using vs2012) to mvc5. After having a lot of issues related to dependencies, I finally found this tutorial and straightened things up so that it
ASP.NET and Web Tools 2013.1 for Visual Studio 2012 has now been released and should resolved the MVC5 intellisense issue with VS 2012.
This release brings a ton of great improvements, and include some fantastic enhancements to ASP.NET MVC 5, Web API 2, Scaffolding and Entity Framework to users of Visual Studio 2012 and Visual Studio 2012 Express for Web.
You can download the update: http://blogs.msdn.com/b/webdev/archive/2013/11/18/announcing-release-of-asp-net-and-web-tools-2013-1-for-visual-studio-2012.aspx