Heterocyclic compounds and uses thereof

A method for treating a proliferative disorder comprising administering to a patient in need thereof a compound represented by structural formula I-a

• or a pharmaceutically acceptable salt thereof, wherein:
• n is 0, 1, or 2;
• m is 0, 1, or 2, wherein m and n are not simultaneously 0;
• W is —O— or —NH—;
• R1 is —OR;
• each R is independently C1-4 alkyl or C1-4 fluoroalkyl;
• R2 is —CF3, Cl, or Br;
• G is —NR3— or —S(O)2—;
• and
• R3 is —C(O)—R, —C(O)OR, —C(O)NHR, —SO2—R, —SO2NH2, —C(O)—C1-4 alkylene-OH or —SO2—C1-4 alkylene-OH;
• and
• wherein the proliferative disorder is a cancer.