Grunt configuration to copy CSS files and change the filename extension to SCSS.

getSCSSFromCSS.js

/**
 * http://gotofritz.net/blog/geekery/rename-files-while-copying-grunt/
 */

module.exports = function( grunt ) {
  "use strict";

  grunt.initConfig({
    //copy all css files to sass directory, and rename to .scss
    copy: {
      getSCSSFromCSS: {
        files: [
          {
            expand: true,
            cwd: 'path/to/css/',
            src: ['**/*.css'],
            dest: 'path/to/sass/',
            rename: function(dest, src) {
              return dest + src.replace(/\.css$/, ".scss");
            }
          }
        ]
      }
    }
  });
  
  grunt.loadNpmTasks('grunt-contrib-copy');

};