Structural factors of annonaceous acetogenins and their semisynthetic analogues related with the toxicity on Spodoptera frugiperda

Toxic and nutritional effects of annonaceous acetogenins and their semisynthetic analogues on Spodoptera frugiperda were evaluated. Structural modification of the natural ACG, blocking the OH flanking THF with MOM, allowed us to suggest the mode of action of ACG in the membrane. Our study emphasizes the role of the flanking OH and acetyl groups of THF with the membrane hydrophilic polar head groups. They are essential structural factors in the ACG that facilitate the intermolecular interaction that dehydrates the membrane and makes it potentially toxic against Spodoptera frugiperda.Fil: Di Toto Blessing, Lilian Edith. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Química Orgánica; ArgentinaFil: Budeguer, Florencia. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Química Orgánica; ArgentinaFil: Ramos, Juan. Universidad de la República. Facultad de Química. Departamento de Química Orgánica; UruguayFil: Bardon, Alicia del Valle. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Química del Noroeste. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Química del Noroeste; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Química Orgánica; ArgentinaFil: Díaz, Sonia Beatriz. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Química Orgánica; ArgentinaFil: Brovetto, Margarita. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Química Orgánica; ArgentinaFil: Seoane, Gustavo. Universidad de la República. Facultad de Química. Departamento de Química Orgánica; UruguayFil: Neske, Adriana. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Química Orgánica; Argentin

Enantiodivergent cyclization by inversion of the reactivity in Ambiphilic molecules

Inverting the reactivity of the functional groups in ambiphilic molecules provides a new synthetic strategy to carry out late‐stage enantiodivergence. Both enantiomers of the final compound can be obtained from a common chiral precursor. As a proof of concept, the synthesis of substituted five‐ and six‐membered oxacycles is described. The key step is the cyclization of an ambiphilic linear precursor bearing a propargylic alcohol and an epoxide linked through an alkyl chain. Through a slight modification of these linear precursors and employing different reaction conditions, these functional groups can inverse their chemical reactivity, producing one enantiomer or another of the final product. This enantiodivergent cyclization involves three stereogenic centers that can undergo fully controlled retention or inversion of their configuration depending on the cyclization pathway that is activated. The cyclization provides late‐stage enantiodivergence, enabling the synthesis of either enantiomers of the oxacycles from a common chiral substrate with total transfer of the enantiomeric purity.This research was supported by the Spanish MINECO and MCIU/AEI (CTQ2014-56362-C2-1-P, CTQ2014-59649-P, PGC2018-094503-B-C22, and PGC2018-094503-B-C21), cofinanced by the European Regional Development Fund (ERDF)Peer reviewe

Chemoenzymatic Synthesis of <i>trans</i>-Tetrahydrofuran Cores of Annonaceous Acetogenins from Bromobenzene

Two types of <i>trans</i>-THF cores, present in acetogenins, have been synthesized by an intramolecular iodoetherification reaction. The starting alkenol was obtained in a few steps from a chiral <i>cis</i>-diol resulting from microbial oxidation of bromobenzene. The cyclization gave complete stereoselectivity for <i>trans</i>-THF cores with either (<i>S</i>,<i>S</i>) or (<i>R</i>,<i>R</i>) configurations at the THF chiral carbons

Iron(III)-catalyzed halogenations by substitution of sulfonate esters

A novel halogenation reaction from sulfonates catalyzed by iron(III) is described. The reaction can be performed as a stoichiometric or a catalytic version. This reaction provides a convenient strategy for the efficient access to structurally diverse secondary chlorides, bromides and iodides. The stereochemical course of the reaction is governed by the substrate and the experimental conditions. Secondary alcohols modified as quisylates or pysylates are substantially more reactive. Aliphatic quisylates proceed with overall inversion of configuration under catalytic conditions. Chemoselectivity in bismesylates was observed in favour of the secondary mesylate. Additionally, based on the experimental results, a possible catalytic cycle for the halogenation has been proposed.Spanish MICINN‐FEDER. Grant Numbers: CTQ2008‐03334/BQU, CTQ2008‐06806‐C02‐01/BQU. Consejo Superior de Investigaciones Científicas (CSIC). Grant Number: PIE 200680I052. MSC Grant Number: RTICC RD06/0020/1046 Canary Islands FUNCIS. Grant Number: PI 01/06. ACIISI Grant Number: PI 2007/02