Total Synthesis of Echinopines A and B: Exploiting a Bio-inspired Late-Stage Intramolecular Cyclopropanation Philippe A. Peixoto, a Jean-Alexandre Richard, a Rene Severin, a and David Y.-K. Chen* ,b a Chemical Synthesis Laboratory@Biopolis, Institute of Chemical and Engineering Sciences (ICES), Agency for Science, Technology and Research (A*STAR), 11 Biopolis Way, The Helios Block, #03-08, Singapore 138667 and b Department of Chemistry, Seoul National University, Gwanak-1 Gwanak-ro, Gwanak-gu, Seoul 151- 742, South Korea E-mail: davidchen@snu.ac.kr