One proposed alternative to await (for CoffeeScript) that is more one-to-one with the generated JavaScript: https://github.com/jashkenas/coffee-script/issues/2762
There's also a discussion[1] at Codeplex on some TypeScript compatible alternatives to async/await.
Anders talks about that problem in this video: http://channel9.msdn.com/Events/Build/2013/9-006