SHMT inhibitors and uses thereof

A compound of Formula II-a:

• or a pharmaceutically acceptable salt thereof, wherein:
• each R1 is independently halogen, —CN, —NO2, —OR, —Cy, or an optionally substituted C1-6 aliphatic group;
• or
• two R1 groups can be taken together with their intervening atoms to form a 5-8 membered partially unsaturated or aryl fused ring having 0-3 heteroatoms independently selected from nitrogen, oxygen or sulfur;
• each R is independently hydrogen or an optionally substituted group selected from C1-6 aliphatic, a 3-8 membered saturated or partially unsaturated monocyclic carbocyclic ring, phenyl, an 8-10 membered bicyclic partially unsaturated or aromatic carbocyclic ring, a 4-8 membered saturated or partially unsaturated monocyclic heterocyclic ring having 1-2 heteroatoms independently selected from nitrogen, oxygen, or sulfur, a 5-6 membered monocyclic heteroaromatic ring having 1-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur, or an 8-10 membered bicyclic partially unsaturated or heteroaromatic ring having 1-5 heteroatoms independently selected from nitrogen, oxygen, or sulfur;
• each Cy is independently an optionally substituted group selected from a 3-8 membered saturated or partially unsaturated monocyclic carbocyclic ring, phenyl, an 8-10 membered bicyclic partially unsaturated or aromatic carbocyclic ring, a 4-8 membered saturated or partially unsaturated monocyclic heterocyclic ring having 1-2 heteroatoms independently selected from nitrogen, oxygen, or sulfur, a 5-6 membered monocyclic heteroaromatic ring having 1-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur, or an 8-10 membered bicyclic partially unsaturated or heteroaromatic ring having 1-5 heteroatoms independently selected from nitrogen, oxygen, or sulfur;
• Rx and Ry are independently hydrogen or an optionally substituted group selected from C1-6 aliphatic or phenyl;
• Rx′ and Ry′ are independently hydrogen or C1-4 alkyl;
• or
• Ry and Ry′ can be taken together with their intervening atoms to form a 3-6 membered saturated ring having 0-3 heteroatoms independently selected from nitrogen, oxygen or sulfur;
• and
• m is 1, 2, 3, or 4.