quick keyboard shortcut for Enable Black & White toggle

Short of writing apple script for creating a new keyboard shortcut, I have looked into all options for adding this as a keyboard shortcut. It would make a huge difference in my workflow to have a keyboard shortcut for this feature.

Current workaround

I have to go to the Color tab and manually click the Enable Black & White box. It makes for toggling the b&w on and off really clunky when I'm trying to compare and contrast images.