Enum to list as an extension?

I have various enums that I use as sources for dropdown lists, In order to provide for a user-friendly description, I added a Description attribute to each enum, and then do the following:

var list = Enum.GetValues(typeof(MyEnum))
               .Cast<MyEnum>()
               .ToDictionary(k => k, v => v.GetAttributeOfType<DescriptionAttribute>().Description)
               .ToList();

The above is repetitive because I have to use it in a lot of places. I tried to add an extension method:

    public static T GetAttributeOfType<T>(this Enum enumVal) where T : System.Attribute
    {
        var type = enumVal.GetType();
        var memInfo = type.GetMember(enumVal.ToString());
        var attributes = memInfo[0].GetCustomAttributes(typeof(T), false);

        return (attributes.Length > 0) ? (T)attributes[0] : null;
    }

    public static KeyValuePair<T, string> ToList<T>(this Enum source) 
    {
        return Enum.GetValues(typeof(T))
                   .Cast<T>()
                   .ToDictionary(k => k, v => v.GetAttributeOfType<DescriptionAttribute>().Description)
                   .ToList();
    }

However, I get an exception:

Cannot convert lambda expression to type 'System.Collections.Generic.IEqualityComparer' because it is not a delegate type

What is the correct way to use it as an extension (using the above 2 methods)?