1. Department
of Small Molecule Process Chemistry, Genentech, Inc., 1 DNA Way, South San Francisco, California 94080, United States
2. Department
of Chemistry, University of California, Berkeley, California 94720, United States
3. Warren
and Katherine Schlinger Laboratory for Chemistry and Chemical Engineering,
Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
4. Department
of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, China