The invention provides spiro[pyrrolidine-2,3'-oxindole] compounds and libraries of these compounds produced by the stereo- and regio-selective reaction of variously substituted isatins, .alpha.-amino acids, and dipolarophiles (e.g., trans-chalcones, acrylate esters, or vinyl oxindoles). The new libraries can be assayed using any of many known screening procedures for activity, e.g., biological activity. For example, the libraries can be screened for activity as drugs (e.g., anticancer drugs, antibiotics, antiviral drugs, antiinflammatory drugs, analgesics, immunomodulators, neuroleptics, sedatives, stimulants, or diagnostic aids), bioseparation agents, or pesticides (e.g., herbicides, insecticides, or rodenticides).