# this is easy...
# grab a string
my $sa ='random,junk no,one,cares about(I,Want,This,stuff) but, (not,this) stuff which&might have-random characters';
# extract the string between the first set of ( and )
my ($sb) = $sa =~ m/\((.+?)\)/;
# split the string on ,
my @ab = split(',',$sb);
# join and butress the string with ^ 
my $sc = '^' . join('^',@ab) . '^';