Need Regular Expression in scala

This is my response

   scala > val a= """{"string":"{\"data\":{\"id\":\"2c91809f4ef7678b014ef86ee28511c2\",\"unitName\":\"gatlir1\",\"owner\":\"gatlir1\",\"description\":\"gatlir1\",\"nofChairs\":0,\"nofBeds\":0,\"nofApptStartWithInHour\":0,\"nofApptDischargeWithInHour\":0,\"modifiedDateTime\":\"Aug 4, 2015 4:18:13 AM\"},\"status\":\"SUCCESS\",\"message\":\"unit_save\"}"}"""

i need to fetch id value from that response in scala. i have stored response in one variable. and i have written regular expression for that and stored in another variable.

Here is the problem , i am getting error. RegEx:

     scala> val b= """{\"id\":\"(\w+)\""""

while inserting regex into "b" , i didn't get any error, but while comparing i am getting error

if i write expression like this

          scala> a.matches(b) 

error:

  java.util.regex.PatternSyntaxException: Illegal repetition
   {\"id\":\"(\w+)\"
   at java.util.regex.Pattern.error(Pattern.java:1955)
   at java.util.regex.Pattern.closure(Pattern.java:3157)
   at java.util.regex.Pattern.sequence(Pattern.java:2134)
   at java.util.regex.Pattern.expr(Pattern.java:1996)
   at java.util.regex.Pattern.compile(Pattern.java:1696)
   at java.util.regex.Pattern.<init>(Pattern.java:1351)
   at java.util.regex.Pattern.compile(Pattern.java:1028)
   at java.util.regex.Pattern.matches(Pattern.java:1133)
   at java.lang.String.matches(String.java:2109)

could any one help me in this..