Compounds and methods for inhibiting mitotic progression

A compound of formula (A):

• or a pharmaceutically acceptable salt thereof;
• wherein:
• Rf1 is hydrogen, or Rf1 and Rf2 together form a bond;
• Rf2 is hydrogen, or Rf2 forms a bond with either Rf1 or Rx;
• each of Rx and Ry independently is hydrogen, fluoro, or an optionally substituted C1-6 aliphatic;
• or Rx and Ry, taken together with the carbon atom to which they are attached, form an optionally substituted 3- to 6-membered cycloaliphatic ring;
• or Rx and Rf2 together form a bond;
• G is hydrogen, an optionally substituted aliphatic or Ring B when Rf1 is hydrogen;
• and G is hydrogen, —OR5, —N(R4)2, —SR5, an optionally substituted aliphatic, or Ring B when Rf1 and Rf2 together form a bond;
• Ring A is a substituted or unsubstituted 5- or 6-membered aryl, heteroaryl, cycloaliphatic, or heterocyclyl ring;
• Ring B is a substituted or unsubstituted aryl, heteroaryl, heterocyclyl, or cycloaliphatic ring;
• Ring C is a substituted or unsubstituted aryl, heteroaryl, heterocyclyl, or cycloaliphatic ring;
• Ra is hydrogen, —C(O)R1, —CO2R1, —SO2R1, or a C1-3 aliphatic having 0-2 substituents independently selected from R3 or R7;
• Re is hydrogen, —OR5, —N(R4)2, —SR5, —NR4C(O)R5, —NR4C(O)N(R4)2, —NR4CO2R6, —N(R4)SO2R6, —N(R4)SO2N(R4)2, or a C1-3 aliphatic optionally substituted with R3 or R7;
• R1 is C1-6 aliphatic or an optionally substituted aryl, heteroaryl, or heterocyclyl group;
• each R1 independently is selected from the group consisting of -halo, —OH, —O(C1-3 alkyl), —CN, —N(R4)2, —C(O)(C1-3 alkyl), —CO2H, —CO2(C1-3 alkyl), —C(O)NH2, and —C(O)NH(C1-3 alkyl);
• each R4 independently is hydrogen or an optionally substituted aliphatic, aryl, heteroaryl, or heterocyclyl group;
• or two R4 on the same nitrogen atom, taken together with the nitrogen atom, form an optionally substituted 5- to 6-membered heteroaryl or 4- to 8-membered heterocyclyl ring having, in addition to the nitrogen atom, 0-2 ring heteroatoms selected from N, O, and S;
• each R5 independently is hydrogen or an optionally substituted aliphatic, aryl, heteroaryl, or heterocyclyl group;
• each R6 independently is an optionally substituted aliphatic or aryl group;
• and
• each R7 independently is an optionally substituted aryl, heterocyclyl, or heteroaryl group.