Compounds having the structure I: ##STR1##

are useful for inducing cell death (apoptosis) and in immunosuppression. In structure I,

• CR¹R² is selected from CHOH, CO, CHF, CF₂ and C(CF₃)OH;
• CR⁶ and CR¹³ are selected from CH, COH and CF;
• CR⁷R⁸, CR⁹R¹⁰ and CR¹¹R¹² are selected from CH₂, CHOH, CO, CHF and CF₂; and
• CR³R⁴R⁵ is selected from CH₃, CH₂OH, CO, COOH, CH₂F, CHF₂ and CF₃;
• such that: at least one of R¹-R¹³ comprises fluorine;
• no more than two of CR³R⁴R⁵, CR⁶, CR⁷R⁸, CR⁹R¹⁰, CR¹¹R¹², and CR¹³ comprises fluorine or oxygen;
• and, when CR¹R² is CHOH, CR³R⁴R⁵ is not CH₂F.