A potent, selective and ATP-competitive mTOR inhibitor (IC₅₀ = 2.1 nM for mTORC1). Torin 2 displays 800-fold selectivity for mTOR over PI3K (cellular EC₅₀ values of 0.25 nM and 200 nM, respectively) and exhibits 100-fold binding selectivity relative to 440 other protein kinases.