Disclosed are compounds of Formula (I): wherein: R2 is phenyl, fluorophenyl, chlorophenyl, trifluorophenyl, methylisoxazolyl, or pyridinyl; R3 is H, CH3, CH2(cyclopropyl), pyridinyl, chloropyridinyl, or methoxypyridinyl: and Ra, Rb, y, and z are defined herein. Also disclosed are methods of using such compounds to inhibit the Notch receptor, and pharmaceutical compositions comprising such compounds. These compounds are useful in treating, preventing, or slowing the progression of diseases or disorders in a variety of therapeutic areas, such as cancer.