The present invention is directed towards an isomer, an enantiomer, a diastereoisomer, or a tautomer of a pyrrolidine compound represented by Formula I: in which the substituents R1, R1a, R2, R2a, R3, A and Q are defined herein; or a prodrug, or a salt thereof, and which bind to IAP BIR domains. In particular, the compounds are useful in treating proliferative disorders such as cancer.