ASP.NET 5 is no longer. Introducing ASP.NET Core 1.0 and .NET core 1.0 .

There are only two hard things in Computer Science: cache invalidation and naming things. - Phil Karlton

It's very easy to armchair quarterback and say that "they should have named it Foo and it 
would be easy" but very often there's many players involved in naming things. ASP.NET is 
a good 'brand' that's been around for 15 years or so. ASP.NET 4.6 is a supported and 
released product that you can get and use now from http://get.asp.net.

UPDATE NOTE: This blog post is announcing this change. It's not done or released yet. 
As of the date/time of this writing, this work is just starting. It will be ongoing over the next 
few months.

However, naming the new, completely written from scratch ASP.NET framework 
"ASP.NET 5" was a bad idea for a one major reason: 5 > 4.6 makes it seem like 
ASP.NET 5 is bigger, better, and replaces ASP.NET 4.6. Not so.

Refer form:
http://www.hanselman.com/blog/ASPNET5IsDeadIntroducingASPNETCore10AndNETCore10.aspx

ASP.NET 5 is dead - Introducing ASP.NET Core 1.0 and .NET Core 1.0