The present disclosure relates to inhibitors of zinc-dependent histone deacetylases (HDACs) useful in the treatment of diseases or disorders associated with an HDAC, e.g., HDAC6, having a Formula I: where R, L, X1, X2, X3, X4, Y1, Y2, Y3, and Y4 are described herein.本發明係關於適用於治療與鋅依賴性組蛋白脫乙醯基酶(HDAC)相關之疾病或病症的HDAC(例如,HDAC6)之抑制劑,其具有式I:其中R、L、X1、X2、X3、X4、Y1、Y2、Y3及Y4如本文中所述。