whoop-de-do /ˌwuːp diː ˈduː, ˌhuːp-/ BrE AmE interjection American English
[ Date: 1900-2000 ; Origin: Perhaps from whoop + to-do ]
used to show that you do not think something that someone has told you is as exciting or impressive as they think it is:
‘He says he’ll give me a $20 raise.’ ‘Well, whoop-de-do.’