61262-97-3Relevant articles and documents
Asymmetric synthesis and structure-activity studies of the fungal metabolites colletorin A, colletochlorin A and their halogenates analogues
Marsico, Giulia,Pignataro, Barbara A.,Masi, Marco,Evidente, Antonio,Casella, Francesca,Zonno, Maria Chiara,Tak, Jun-Hyung,Bloomquist, Jeffrey R.,Superchi, Stefano,Scafato, Patrizia
, p. 3912 - 3923 (2018/06/08)
The first asymmetric total synthesis of both enantiomers of the natural products colletorin A and colletochlorin A is presented. The proposed methodology is based on the coupling reaction between highly substituted aromatic Gilman cuprates and optically active allyl bromides, in turn obtained by Sharpless asymmetric dihydroxylation. The latter ensured a high degree of regio- and stereocontrol in the enantioselective step of the synthesis. The same synthetic strategy has been also applied for the preparation of differently halogenated synthetic analogues of colletochlorin A in high enantiomeric purity. The enantioselective synthesis of colletorin A and colletochlorin A allows to reliably assign their absolute configuration. Preliminary assessment of their herbicidal and insecticidal properties evidence the possibility to modulate the bioactivity of these compounds, highlighting its dependence on both the absolute stereochemistry and the halogen nature.
Reconstitution of biosynthetic machinery for indole-diterpene paxilline in Aspergillus oryzae
Tagami, Koichi,Liu, Chengwei,Minami, Atsushi,Noike, Motoyoshi,Isaka, Tetsuya,Fueki, Shuhei,Shichijo, Yoshihiro,Toshima, Hiroaki,Gomi, Katsuya,Dairi, Tohru,Oikawa, Hideaki
supporting information, p. 1260 - 1263 (2013/03/29)
Indole-diterpenes represented by paxilline share a common pentacyclic core skeleton derived from indole and geranylgeranyl diphosphate. To shed light on the detailed biosynthetic mechanism of the paspaline-type hexacyclic skeleton, we examined the reconstitution of paxilline biosynthetic machinery in Aspergillus oryzae NSAR1. Stepwise introduction of the six pax genes enabled us to isolate all biosynthetic intermediates and to synthesize paxilline. In vitro and in vivo studies on the key enzymes, prenyltransferase PaxC and cyclase PaxB, allowed us to elucidate actual substrates of these enzymes. Using the isolated and the synthesized epoxide substrates, the highly intriguing stepwide epoxidation/cyclization mechanism for the construction of core structure has been confirmed. In addition, we also demonstrated "tandem transformation" to simultaneously introduce two genes using a single vector (paxG/paxB, pAdeA; paxP/paxQ, pUNA). This may provide further option for the reconstitution strategy to synthesize more complex fungal metabolites.
Total Syntheses of (+)-Thyrsiferol, (+)-Thyrsiferyl 23-Acetate, and (+)-Venustatriol
Hashimoto, Masaru,Kan, Toshiyuki,Nozaki, Koji,Yanagiya, Mitsutoshi,Shirahama, Harushia,Matsumoto, Takeshi
, p. 5088 - 5107 (2007/10/02)
The first total syntheses of (+)-thyrsiferol (1), (+)-thyrsiferyl 23-acetate (3), and (+)-venustatriol (5) have been accomplished in a stereoselective manner.An effective synthetic scheme to construct the BC ring system, which adopts a chair/twist-boat conformation, was first developed by means of a model study.This method involves stereoselective formation of the strained C ring by intramolecular attack of the C7-hydroxyl group at the C3-postion of the 2,3-epoxy alcohol, employing titanium tetraisopropoxide as an acidic activator.Based on the information accumulated in the model study and retrosynthetic considerations, the total syntheses of 1,3, and 5 were performed in the sequence of (1) construction of the BC ring system equipped with a C1-C6 carbon unit, (2) elongation of the C17-C24 carbon chain, (3) formation of a D ring through the stereoselective epoxidation of the 4-en-1-ol system and successive cyclization, and (4) construction of the A ring by bromonium ion induced cyclization of the 4-en-1-ol system.
