I have a simple wildcard routing rule I want to apply for my Azure web app.
If simply want all URL's that resolve to this server & site to redirect to index.html you could use this rewrite section:
This is very similar to what you have except some minor syntax fixes e.g. the pattern should be ".*" and the rewrite URL target simply "index.html". Note this means that ALL URL's to your site will be rewritten, even for other resources like CSS and JS files, images etc. So you'd better be fetching your resources from other domains.