Hi knickernicker:
First off your DD is absolutely entitled to feel sitting around chatting (especially if it's a bit catty) really isn't for her. However, she should be encouraged to be friendly to everyone (girls & boys) in the class, say hello, pay a compliment, ask what they're doing, etc....
Second - have a good look around the playground. Are there other things to do? Hopscotch, skipping ropes, bars, climbing frame, scooters, etc... If so point them out to her and suggest she just does it on her own.
Third - quiet by nice activities - does the school allow them to draw with chalks on the playground? Can she bring out paper & a pencil and draw something. Can she bring out a book?
Fourth - trust in time. Time will pass and she will have shared experiences with these kids and that will result in friendships. She may even make friends in other forms/ years because they all have recess together. Certainly consider signing her up for an after school activity or two - so that she's having time with friends outside the normal day to day of school.
A combination of #2-#4 will mean that she will be occupied during play times and that hopefully gradually she'll have friends to play with.
DD2 didn't like endlessly playing tig in her class - she was usually chosen to be 'it' and several girls kept changing the rules every time she caught them. So she started to do her own thing. Playing hopscotch on her own - at least she was enjoying herself or building landybug shelters/ rescuing insects from the playground. Gradually people would drift by and ask what she was doing, she'd explain and ask if they wanted to join in/ help - and now she has quite a group of friends who play with her. She's not their BFF perhaps, but they know they can play nicely and quietly with her when they don't feel so well, they don't want to play that game again, etc...
This didn't happen over night - I'd say it took 2-3 terms, but I can genuinely say now she's in Y4 - things are much happier and she's learned to be her own best company, which is no bad thing.
HTH