Salinosporamide A is a salinosporamide in which the core (1R)-6-oxa-2-azabicyclo[3.2.0]heptane-3,7-dione skeleton is substituted at positions 1, 4, and 5 by (1S)-cyclohex-2-en-1-yl(hydroxy)methyl, 2-chloroethyl, and methyl groups, respectively (the 1R,4R,5S diastereoisomer). A potent proteasome inhibitor, it has attracted interest for potential use in the treatment of various cancers. It has a role as an antineoplastic agent and a proteasome inhibitor. It is a salinosporamide, an organochlorine compound, an organic heterobicyclic compound, a beta-lactone and a gamma-lactam.