Modular synthesis of 1,2-azaborines via ring-opening bn-isostere benzannulation

A compound having the structure

• or a pharmaceutically-acceptable salt thereof, or a solvate thereof, wherein
• R1 is a carbon-linked substituent having no more than 40 non-H atoms;
• R2 is a carbon-linked substituent having no more than 40 non-H atoms;
• R3 is H or a substituent having no more than 40 non-H atoms, and
• L3 is selected from the group consisting of a bond, —C(O)—, —S—, —S(O)2—, —O—, —NR7—, —C(O)NR7—, —NR7C(O)—, —C(S)NR7—, —NRIC(S)—, —O(O)0—, —OC(O)—, —C(O)S—, —SC(O)—, —C(S)O—, —OC(S)—, —C(S)S—, —SC(S)—, —S(O)1-2O—, —OS(O)1-2—, —S(O)12NR7— and —NR7S(O)12—, or
• -L3-R3 is halo, nitro, or cyano;
• R4 is H or a substituent having no more than 40 non-H atoms, and
• L4 is selected from the group consisting of a bond, —C(O)—, —S—, —S(O)1-2—, —O—, —NR7—, —C(O)NR7—, —NR7C(O)—, —C(S)NR—, —NFR7C(S)—, —O(O)0—, —OC(O)—, —O(O)S—, —SC(O)—, —C(S)O—, —OC(S)—, —C(S)S—, —SC(S)—, —S(O)1-2O—, —OS(O)1-2—, —S(O))2NR7— and —NR7S(O)1-2—, or
• -L4-R4 is halo, nitro, or cyano;
• R6 is H or a substituent having no more than 40 non-H atoms, and
• L6 is selected from the group consisting of a bond, —C(O)—, —S—, —S(O)1-2—, —O—, —NR7—, —C(O)NR7—, —NR7C(O)—, —C(S)NR7—, —NR7C(S)—, —C(O)O—, —OC(O)—, —C(O)S—, —SC(O)—, —C(S)O—, —OC(S)—, —C(S)S—, —SC(S)—, —S(O)1-2O—, —OS(O)1-2—, —S(O)12NR7— and —NR7S(O)1-2—, or
• -L3-R3 is halo, nitro, or cyano;
• wherein
• each R6 is independently selected from the group consisting of hydrogen, C1-C3 alkyl and —C(O)(C1-C3 alkyl).