The present invention relates to Phosphate Substituted Quinolizine Derivatives of Formula (I): and pharmaceutically acceptable salts or prodrug thereof, wherein X, Y, R1, R2, R3, R4, R5, R9 and R10 are as defined herein. The present invention also relates to compositions comprising at least one Phosphate Substituted Quinolizine Derivative, and methods of using the Phosphate Substituted Quinolizine Derivatives for treating or preventing HIV infection in a subject.