A compound of formula I: or a pharmaceutically acceptable salt thereof, wherein, independently for each occurrence: W is N or CR 1, or 1 W is a bond and the remaining W are N, NR 1, or CR 1, wherein up to 2 W are N or NR 1; a dashed circle denotes unsaturation; R 1 is H, C1-C6 alkyl, C1-C6 haloalkyl, halo, CN, SO 2 R 7, SR 7, SOR 7, NR 7 COR 7, NR 7 CO 2 R 7, CON(R 7) 2, SO 2 N(R 7) 2, CF 3, OCF 3, OCHF 2, an optionally substituted aryl, heteroaryl, cycloalkyl, or heterocycloalkyl, or a straight chain, branched, or cyclic (C1-C8)-R 8 wherein up to two CH 2 units may be replaced with O, CO, S, SO, SO 2, CF 2, or NR 7; R 2 is C1-C6 alkyl, C1-C6 alkoxy, halo, CN, OR 7, N(R 7) 2, NR 7 SO 2 R 7, SO 2 R 7, SR 7, SOR 7, CO 2 R 7, NR 7 COR 7, NR 7 CO 2 R 7, CON(R 7) 2, SO 2 N(R 7) 2, CF 3, OCF 3, OCHF 2, CH 2 OCHF 2, CH 2 OCH 2 CHF 2, an optionally substituted aryl, heteroaryl, C3-C8 cycloalkyl, or heterocycloalkyl, or a straight chain, branched, or cyclic (C1-C8)-R 8 wherein up to two CH 2 units may be replaced with O, CO, S, SO, SO 2 or NR 7; R 3 is C1-C6 alkyl or C3-C8 cycloalkyl, wherein up to two CH 2 units may be replaced by O, NR 8, S, SO, SO 2, or 2 occurrences of R 3 taken together form a C3-C8 cycloalkyl group; R 7 is H, C1-C6 alkyl or fluoroalkyl, or C3-C8 cycloalkyl, or 2 R 7 taken together with the atoms to which they are attached form a ring; R 8 is H, CF 3, CO 2 R 7, OH, an optionally substituted aryl, heteroaryl, C3-C8 cycloalkyl, or heterocycloalkyl, N(R 7) 2, NR 7 COR 7, CON(R 7) 2, CN, or SO 2 R 7; A is aryl; X is O, S, or SO; n is an integer from 1 to 4 inclusive; and o is an integer from 0 to 4 inclusive; provided that: a) when R 2 is OH, another R 2 is not C1-C6 alkyl. W is N or CR 1, or 1 W is a bond and the remaining W are N, NR 1, or CR 1, wherein up to 2 W are N or NR 1; R 1 is H, C1-C6 alkyl, C1-C6 haloalkyl, halo, CN, SO 2 R 7, SR 7, SOR 7, NR 7 COR 7, NR 7 CO 2 R 7, CON(R 7) 2, SO 2 N(R 7) 2, CF 3, OCF 3, OCHF 2, an optionally substituted aryl, heteroaryl, cycloalkyl, or heterocycloalkyl, or a straight chain, branched, or cyclic (C1-C8)-R 8 wherein up to two CH 2 units may be replaced with O, CO, S, SO, SO 2, CF 2, or NR 7; R 2 is C1-C6 alkyl, C1-C6 alkoxy, halo, CN, OR 7, N(R 7) 2, NR 7 SO 2 R 7, SO 2 R 7, SR 7, SOR 7, CO 2 R 7, NR 7 COR 7, NR 7 CO 2 R 7, CON(R 7) 2, SO 2 N(R 7) 2, CF 3, OCF 3, OCHF 2, CH 2 OCHF 2, CH 2 OCH 2 CHF 2, an optionally substituted aryl, heteroaryl, C3-C8 cycloalkyl, or heterocycloalkyl, or a straight chain, branched, or cyclic (C1-C8)-R 8 wherein up to two CH 2 units may be replaced with O, CO, S, SO, SO 2 or NR 7; R 3 is C1-C6 alkyl or C3-C8 cycloalkyl, wherein up to two CH 2 units may be replaced by O, NR 8, S, SO, SO 2, or 2 occurrences of R 3 taken together form a C3-C8 cycloalkyl group; R 7 is H, C1-C6 alkyl or fluoroalkyl, or C3-C8 cycloalkyl, or 2 R 7 taken together with the atoms to which they are attached form a ring; R 8 is H, CF 3, CO 2 R 7, OH, an optionally substituted aryl, heteroaryl, C3-C8 cycloalkyl, or heterocycloalkyl, N(R 7) 2, NR 7 COR 7, CON(R 7) 2, CN, or SO 2 R 7; A is aryl; X is O, S, or SO; n is an integer from 1 to 4 inclusive; and o is an integer from 0 to 4 inclusive; a) when R 2 is OH, another R 2 is not C1-C6 alkyl.