A compound of structural Formula I or a salt thereof, wherein: E is an E3 ligase ligand; L is chosen from *-(CH 2) n CH 2 N(R 7)CO(CH 2) p CH 2 -**, *-CO(CH 2) n CH 2 -**, *-CO(CH 2) q O(CH 2 CH 2 O) n CH 2 (CH 2) p -**, *-(CH 2) n CH 2 -**, *-(CH 2) q O(CH 2 CH 2 O) n CH 2 (CH 2) p - * *, and * represents the point of attachment to E; ** represents the point of attachment to X; X is chosen from O, NR 10, S, SO, and SO 2; R 1 and R 2 are independently chosen from H, alkyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl, alkoxy, alkenyl, alkynyl, halo, alkylamino, dialkylamino, cyano, and hydroxy; R 3 and R 4 are independently chosen from H, alkyl, alkoxy, alkenyl, alkylnyl, and hydroxyl, or R 3 and R 4, together with the atom to which they are attached, form a cycloalkyl or heterocycloalkyl ring, either of which is optionally substituted with 1, 2, or 3 R 11 groups; R 5 and R 6 are independently chosen from H, alkyl, haloalkyl, alkoxy, amino, alkylamino, dialkylamino, cycloalkyl, (cycloalkyl)alkyl, heterocycloalkyl, (heterocycloalkyl)alkyl, CONR 12 R 13, SO 2 NR 12 R 13, SOR 14, SO 2 R 14, halo, hydroxy, and cyano, or R 5 and R 6, together with the atom to which they are attached, form a cycloalkyl or heterocycloalkyl ring, either of which is optionally substituted with 1, 2, or 3 R 15 groups; R 7 is chosen from H, alkyl, cycloalkyl, (cycloalkyl)alkyl, (CH 2) t COOH, alkylcarbonyl, and -CO(CH 2) t COOH; R 8 and R 9 are independently chosen from H, alkyl, alkylcarbonyl, cycloalkylcarbonyl, alkoxycarbonyl, alkylsulfonyl, -(CH 2) t COOH, - CO(CH 2) t COOH, -COO(CH 2) t COOH, and -(CH 2) t SO 2 OH. R 10 is chosen from H, alkyl, alkoxyalkyl, cycloalkyl, and heterocycloalkyl; each R 11 is independently chosen from alkyl, cycloalkyl, heterocycloalkyl, alkoxy, cyano, halo, and hydroxy; each R 12 and R 13 is independently chosen from H, alkyl, cycloalkyl, and heterocycloalkyl; each R 14 is independently chosen from alkyl, cycloalkyl, and heterocycloalkyl; each R 15 is independently chosen from alkyl, cycloalkyl, heterocycloalkyl, alkoxy, cyano, halo, and hydroxy; n and p are independently chosen from 0-11, inclusive; q is chosen from 0-11, inclusive; r and s are independently chosen from 1-4, inclusive; t is chosen from 1-8, inclusive; and E is chosen from E is an E3 ligase ligand; L is chosen from *-(CH 2) n CH 2 N(R 7)CO(CH 2) p CH 2 -**, *-CO(CH 2) n CH 2 -**, *-CO(CH 2) q O(CH 2 CH 2 O) n CH 2 (CH 2) p -**, *-(CH 2) n CH 2 -**, *-(CH 2) q O(CH 2 CH 2 O) n CH 2 (CH 2) p - * *, and * represents the point of attachment to E; ** represents the point of attachment to X; X is chosen from O, NR 10, S, SO, and SO 2; R 1 and R 2 are independently chosen from H, alkyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl, alkoxy, alkenyl, alkynyl, halo, alkylamino, dialkylamino, cyano, and hydroxy; R 3 and R 4 are independently chosen from H, alkyl, alkoxy, alkenyl, alkylnyl, and hydroxyl, or R 3 and R 4, together with the atom to which they are attached, form a cycloalkyl or heterocycloalkyl ring, either of which is optionally substituted with 1, 2, or 3 R 11 groups; R 5 and R 6 are independently chosen from H, alkyl, haloalkyl, alkoxy, amino, alkylamino, dialkylamino, cycloalkyl, (cycloalkyl)alkyl, heterocycloalkyl, (heterocycloalkyl)alkyl, CONR 12 R 13, SO 2 NR 12 R 13, SOR 14, SO 2 R 14, halo, hydroxy, and cyano, or R 5 and R 6, together with the atom to which they are attached, form a cycloalkyl or heterocycloalkyl ring, either of which is optionally substituted with 1, 2, or 3 R 15 groups; R 7 is chosen from H, alkyl, cycloalkyl, (cycloalkyl)alkyl, (CH 2) t COOH, alkylcarbonyl, and -CO(CH 2) t COOH; R 8 and R 9 are independently chosen from H, alkyl, alkylcarbonyl, cycloalkylcarbonyl, alkoxycarbonyl, alkylsulfonyl, -(CH 2) t COOH, - CO(CH 2) t COOH, -COO(CH 2) t COOH, and -(CH 2) t SO 2 OH. R 10 is chosen from H, alkyl, alkoxyalkyl, cycloalkyl, and heterocycloalkyl; each R 11 is independently chosen from alkyl, cycloalkyl, heterocycloalkyl, alkoxy, cyano, halo, and hydroxy; each R 12 and R 13 is independently chosen from H, alkyl, cycloalkyl, and heterocycloalkyl; each R 14 is independently chosen from alkyl, cycloalkyl, and heterocycloalkyl; each R 15 is independently chosen from alkyl, cycloalkyl, heterocycloalkyl, alkoxy, cyano, halo, and hydroxy; n and p are independently chosen from 0-11, inclusive; q is chosen from 0-11, inclusive; r and s are independently chosen from 1-4, inclusive; t is chosen from 1-8, inclusive; and E is chosen from