The invention provides novel inhibitors of IAP that are useful as therapeutic agents for treating malignancies where the compounds have the general formula I: ##STR00001## wherein X, Y, A, R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.4', R.sub.5, R.sub.5', R.sub.6 and R.sub.6' are as described herein.