Disclosed are compounds of Formula (I): (I) or a salt thereof, wherein: X is CH or N; Y is CH or N; R1 is —OH or —OP(O)(OH)2; L is —CR3═N—O—CRaRa— or CRaR—O—N═CR3; L2 is a bond, —C(O)—, or S(O)2—; and R2, R3, Ra, m, and n are defined herein. Also disclosed are methods of using such compounds as selective agonists for G protein coupled receptor S1P1, 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 autoimmune diseases and vascular disease.