Update: The assembly reference to System.Data.Entity is selected in the Reference Manager.
Error 1 The type or namespace name 'Infrastructure' does not exist in the namespace 'System.Data.Entity' (are you missing an assembly reference?)
C:\Users\johndoe\Documents\Visual Studio 2012\Projects\MvcApplication1\MvcApplication1\Global.asax.cs
On the ribbon, select the dropdown that says "Debug" and select Configuration Manager. From there, select the dropdown under "Platform", click New, and now under New platform select x86. Hit ok and close the configuration manager. Try building your project.
System.data.entity is a 32-bit assembly so you may have to build your project as x86. If this doesn't work, you can follow the same steps above and select x64 and try again.
AFAIK you shouldn't have to do this, I followed your steps excatly and had no issues building under Any CPU.
You can also try installing entityframework. Right click on references, manage nuget packages, click online and you should see EntityFramework come up in the center column.