$string = q{This is \'not\' it yet... 'this \'is\' it!'}; 
  
($quoted) = $string =~ m{ 
  ^ 
 
  # advance past all the non-wanted stuff 
  [^'\\]* (?: \\. [^'\\]* ) *   
 
  # match and save what we want 
  ' ( [^'\\]* (?: \\. [^'\\]* ) * ) ' 
}x;