2017.2.0f3 OSX MonoDevelop can't find UnityEngine

As soon as I put a new project in .NET 4.6 Experimental mode I get this on OSX (High Sierra), runs fine on my Windows 10 box, but my laptop is a MacBook Pro it’s what I take with me on the go and I’m on the go a lot. I need 4.6 working for a lot of reasons with the projects I’m doing. UnityEngine won’t find in the editor, and it’s acting like the System references aren’t found as you can see. This is on a fresh install of OSX High Sierra with Unity 2017.2.0f3. On OSX I don’t have the option of using Visual Studio just Mono unless someone knows how to get it working with VS for Mac or VS Code. Any ideas??

Just tried on 2017.3.0b8 and got the same result.

Got it working with Visual Studio for Mac though, now everything is rocking.