This invention relates to the identification of a novel class of therapeutic agents which selectively target and kill tumor cells and certain other types of diseased cells, and to compositions comprising lipoic acid derivatives which poison the pyruvate dehydrogenase complex specifically in such cells. This invention also provides for methods of using therapeutically effective amounts of the lipoic acid derivatives for the treatment of cancer and other diseases. The lipoic acid derivatives described herein have a wide range of preventive and therapeutic applications.