1. Contribution from the Department of Chemistry and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, Chemistry Department, Emory University, 1521 Pierce Drive, Atlanta, Georgia 30322, Winship Cancer Institute, Emory University School of Medicine, 1365-B Clifton Rd., Atlanta, Georgia 30322, and...