title: Synthesis of the N-acetylcysteamine thioester of seco-proansamitocin.
abstract: [structure: see text] The enantioselective total synthesis of the N-acetylcysteamine thioester of seco-proansamitocin, a key biosynthetic intermediate of the highly potent antitumor agent ansamitocin, is described, which twice utilizes the Nagao acetate aldol reaction, as well as an indium-mediated alkynylation of a benzyl bromide followed by carboalumination. The key step is a Heck reaction between two terminal alkenes for merging the two major fragments.
authors.affiliation: Institut für Organische Chemie der Universität Hannover, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Frenzel
authors.forename: Marco
authors.initials: M
authors.lastname: Brünjes
authors.forename: Monika
authors.initials: M
authors.lastname: Quitschalle
authors.forename: Andreas
authors.initials: A
authors.lastname: Kirschning
mesh_terms: D003543:Cysteamine / Q000031:analogs & derivatives* / Q000737:chemistry; D004952:Esters; D008453:Maytansine / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry
chemical_list: D004952:Esters; C507695:seco-proansamitocin; C023704:2-acetamidoethanethiol; D008453:Maytansine; D003543:Cysteamine