Bet protein degraders

A compound having Formula I:

• or a pharmaceutically acceptable salt or solvate thereof, wherein:
• B is selected from the group consisting of:
• R1 is selected from the group consisting of optionally substituted aryl, optionally substituted heteroaryl, and —N(H)R3;
• Q1 is ═CH— and Q2 is —N═;
• or
• Q1 is ═N— and Q2 is —CH═;
• or
• Q1 is ═N— and Q2 is —N═;
• R3 is selected from the group consisting of optionally substituted aryl and optionally substituted heteroaryl;
• X is selected from the group consisting of —C(═O)N(R2a)—, —CH2N(R2b)—, —CH2O—, —N(R2c)—, —O—, and —CH2—;
• wherein the nitrogen atom of —C(═O)N(R2a)— and —CH2N(R2b)— is attached to L, and the oxygen atom of —CH2O— is attached to L;
• L is selected from the group consisting of alkylenyl, heteroalkylenyl, and —(CH2)m—W—(CH2)n—;
• W is selected from the group consisting of optionally substituted phenylenyl, optionally substituted 5-membered heteroarylenyl, and optionally substituted 6-membered heteroarylenyl;
• m is 0, 1, 2, 3, 4, 5, 6, or 7;
• n is 0, 1, 2, 3, 4, 5, 6, 7, or 8;
• Y is selected from the group consisting of —C≡C—, —CH2—, —O—, —N(R2d)—, —C(═O)N(R2e)—, —N(R2f)C(═O)CH2O—, and —N(R2g)C(═O)CH2N(R2h)—;
• or
• Y is absent;
• wherein the carboxamide nitrogen atom of —N(R2f)C(═O)CH2O— and —N(R2g)C(═O)CH2N(R2h)—, and the carbon atom of —C(═O)N(R2e)— is attached to L;
• R2a, R2b, R2c, R2d, R2e, R2f, R2g, and R2h are each independently selected from the group consisting of hydrogen and C1-4 alkyl;
• Z is selected from the group consisting of —CH2 and —C(═O)—;
• and
• R5 is selected from the group consisting of hydrogen and fluoro,
• with the proviso that Y is absent when B is B-2.