Kent Dybvig (Cadence Research, Cisco Systems) has released the commercial scheme compiler Chez Scheme (scheme.com) as open source on GitHub. Chez Scheme is a native code generating optimizing compiler for R6RS focusing on performance and productivity. It supports cross-compilation, threading, and many other extensions. Current version is 9.4.

I'm excited to see what the community will build with this great tool.

https://github.com/cisco/chezscheme