(2R,4S)-4-((t-Butoxycarbonyl)amino)-1,2-dihydroxy-2,6-dimethyl-3-oxohepan-4-tyl is an intermediate used in the synthesis of Carfilzomib (2S,4S)-Diol (C183495), which is a derivative of Carflizomib (C183460), a second-generation proteasome inhibitor that is used as a treatment in relapsed and refractory multiple myeloma.