Passing variables inside rails internationalization yml file

I want to use variables declared in yml file right there. For example, I declared site_name and want to use it below in description.

en:
  site_name: &site_name "Site Name"
  static_pages:
    company:
      description: *site_name #this works fine
      description: "#{*site_name} is an online system" #this doesn't work

How can I combine *site_name variable with additional text?