Bridgehead amine ring-fused indoles and indolines

A compound of formula (I-a):

• or a pharmaceutically acceptable salt thereof, wherein
• a is a single or double bond;
• X is O, S, S(O), S(O)2, or a bond;
• L is —[C(Ra)(Rb)]p—, —[C(Ra)(Rb)]q1—[(CRc)═(CRd)]—[C(Ra)(Rb)]q2—,—[C(Ra) (Rb)]r1—[C≡C]—[C(Ra)(Rb)]r2—, —[C(Ra) (Rb)]s-cyclopropylene-[C(Ra)(Rb)]t—, or a bond;
• or
• X and L taken together are a bond;
• Q is substituted or unsubstituted monocyclic aryl, substituted or unsubstituted bicyclic aryl, substituted or unsubstituted monocyclic heteroaryl, or substituted or unsubstituted bicyclic heteroaryl;
• R2 is hydrogen, C1-C4 alkyl, C2-C4 alkenyl, or C2-C4 alkynyl, wherein C1-C4 alkyl, and the saturated carbon atoms of C2-C4 alkenyl and C2-C4 alkynyl, can be unsubstituted or substituted by hydroxyl, C1-C8 alkyl, C1-C8 haloalkyl, carboxy, or alkoxycarbonyl;
• R3 is hydrogen, halogen, C1-C5 haloalkyl, C1-C5 alkoxy, C1-C5 haloalkoxy, or cyano;
• Ra, Rb, Rc, and Rd are, at each occurrence, independently hydrogen, halogen, C1-C8 alkyl, C1-C8 haloalkyl, carboxy, or alkoxycarbonyl;
• p is 1, 2, 3, 4, or 5;
• q1 and q2 are independently 0, 1, 2, or 3, provided that the sum of q1 and q2 is 0, 1, 2, or 3;
• r1 and r2 are independently 0, 1, 2, or 3, provided that the sum of r1 and r2 is 0, 1, 2, or 3;
• s is 0, 1 or 2;
• and
• t is 0 or 1;
• wherein Q, when substituted, is independently substituted with 1, 2, 3, 4, or 5 substituents, wherein the substituent is halogen, cyano, C1-C5 haloalkyl, C1-C5 alkyl, C2-C5 alkenyl, C2-C5 alkynyl, hydroxy, C1-C5 alkoxy, —O—C1-C5 haloalkyl, —S—C1-C5 alkyl, —S—C1-C5 haloalkyl, —SO2—C1-C5 alkyl, —SO2—C1-C5 haloalkyl, C1-C5 cyanoalkyl, or —NO2.