Bifunctional compounds for degrading BTK via ubiquitin proteosome pathway

A compound of Formula (X):

• or a pharmaceutically acceptable salt thereof, wherein:
• R1 is C1-3 alkyl;
• ring A is phenyl, 5-6 membered partially or fully unsaturated monocyclic heterocycle, 9-10 membered bicyclic aryl, or 9-10 membered bicyclic heteroaryl, wherein the heterocycle and the bicyclic heteroaryl of ring A each independently have 1-3 heteroatoms independently selected from N, O, or S;
• L is —X1—X2—X3—X4—X5—;
• X1 is —C(O)—N(R)—, —N(R)—C(O)—, —(O—CH2—CH2)m—, —O(C6H4)—, —(O—CH2—CH2—CH2)m—, —C1-5 alkyl-, 7-12 membered spiro bicyclic heterocycloalkyl having 1-3 heteroatoms independently selected from N, O, or S wherein the bicyclic heterocycloalkyl of X1 is optionally substituted with —CH3, or 4-6 membered monocyclic heterocycloalkyl having 1-2 heteroatoms independently selected from N, O, or S wherein the monocyclic heterocycloalkyl of X1 is optionally substituted with —CH3;
• X2 is a bond, —(O—CH2—CH2)n—, —(CH2—CH2—O)n—, —N(R)—C(O)—, —N(R)—, —C(O)—, —C1-5 alkyl-, 4-6 membered monocyclic cycloalkyl, or 4-6 membered monocyclic heterocycloalkyl having 1-2 heteroatoms independently selected from N, O, or S;
• X3 is a bond, —C1-4 alkyl-, —C≡C—, 4-6 membered cycloalkyl, —N(R)—, —(O—CH2—CH2)p—, —(CH2—CH2—O)p—, 4-6 membered heterocycloalkyl having 1-2 heteroatoms independently selected from N, O, or S wherein the heterocycloalkyl is optionally substituted with —CH3 or —N(R)—;
• X4 is a bond, —CH2—CH2—N(R)—, —N(R)—, —C1-4alkyl-, —(O—CH2—CH2—CH2)m—, a 5-6 membered saturated, partially unsaturated, or fully unsaturated carbocycle, or a 5-6 membered saturated, partially unsaturated, or fully unsaturated heterocycle having 1-3 heteroatoms independently selected from N, O, or S;
• X5 is a bond, —C1-4 alkyl-, —N(R)—, or —C(O)—N(R)—;
• each R is independently —H or —C1-3 alkyl;
• each of m, n, and p is independently an integer from 1 to 3;
• and
• Y is
• wherein:
• each R2 is independently halo or C1-4 alkyl;
• each Z is —C(RA)2— or —C(O)—;
• each RA is independently —H or C1-4 alkyl;
• and
• q is 0, 1, or 2.