title: Concise Total Synthesis of (+)-Bionectins A and C.
abstract: The concise and efficient total synthesis of (+)-bionectins A and C is described. Our approach to these natural products features a new and scalable method forerythro-β-hydroxytryptophan amino acid synthesis, an intramolecular Friedel-Crafts reaction of a silyl-tethered indole, and a new mercaptan reagent for epipolythiodiketopiperazine (ETP) synthesis that can be unravelled under very mild conditions. In evaluating the impact of C12-hydroxylation, we have identified a unique need for an intramolecular variant of our Friedel-Crafts indolylation chemistry. Several key discoveries including the first example of permanganate-mediated stereoinvertive hydroxylation of the α-stereocenters of diketopiperazines as well as the first example of a direct triketopiperazine synthesis from a parentcyclo-dipeptide are discussed. Finally, the synthesis of (+)-bionectin A and its unambiguous structural assignment through X-ray analysis provides motivation for the reevaluation of its original characterization data and assignment.
authors.affiliation: Massachusetts Institute of Technology, Department of Chemistry, 77 Massachusetts Avenue 18-292, Cambridge, MA 02139-4307, USA. movassag@mit.edu.
authors.forename: Alexis
authors.initials: A
authors.lastname: Coste
authors.forename: Justin
authors.initials: J
authors.lastname: Kim
authors.forename: Timothy C
authors.initials: TC
authors.lastname: Adams
authors.forename: Mohammad
authors.initials: M
authors.lastname: Movassaghi