3036-18-8Relevant articles and documents
Stereoselective Cross-Coupling of Grignard Reagents and Conjugated Dienylbromides using Iron Salts with Magnesium Alkoxides
Chourreu, Pablo,Gayon, Eric,Guerret, Olivier,Guillonneau, Lo?c,Lefèvre, Guillaume
supporting information, p. 4701 - 4706 (2021/09/10)
A convenient procedure allowing iron-catalyzed cross-coupling of alkyl or aryl Grignard reagents and conjugated dienyl bromides is reported, relying on the use of cheap and non-toxic magnesium alkoxides as sole additives. An excellent stereoselectivity is observed in the alkyl-dienyl series. This sequence has been applied to the synthesis of the sex pheromone of codling moth, illustrating its applicability for obtaining targets of industrial interest. Preliminary mechanistic studies carried out on the aryl-dienyl cross-coupling suggest that in situ generated ate homoleptic organoiron(II) species act as catalytically relevant intermediates. A modified preparative method for the realization of THF solutions of dienyl bromides as “ready-to-use” coupling partners is also discussed, circumventing the thermal instability of those derivatives.
Reconstitution of a Type II Polyketide Synthase that Catalyzes Polyene Formation
Du, Danyao,Katsuyama, Yohei,Shin-ya, Kazuo,Ohnishi, Yasuo
supporting information, p. 1954 - 1957 (2018/02/10)
While type II polyketide synthases (PKSs) are known for producing aromatic compounds, a phylogenetically new subfamily of type II PKSs have been recently proposed to synthesize polyene structures. Here we report in vitro analysis of such a type II PKS, IgaPKS for ishigamide biosynthesis. The ketoreductase (Iga13) and dehydratase (Iga16) were shown to catalyze the reduction of a β-keto group and dehydration of a β-hydroxy group, respectively, to form a trans double bond. Incubation of the acyl carrier protein (Iga10), the ketosynthase/chain length factor complex (Iga11–Iga12), Iga13 and Iga16 with malonyl and hexanoyl-CoAs and NADPH followed by KOH hydrolysis resulted in the formation of four unsaturated carboxylic acids (C8, C10, C12, and C14), indicating that IgaPKS catalyzes tetraene formation by repeating the cycle of condensation, keto-reduction and dehydration with strict stereo-specificity. We propose “highly reducing type II PKS subfamily” for the polyene-producing type II PKSs.
Teratogenic effects of diatom metabolites on sea urchin Paracentrotus lividus embryos
Romano, Giovanna,Miralto, Antonio,Ianora, Adrianna
experimental part, p. 950 - 967 (2010/12/18)
The diatom-derived polyunsaturated aldehydes (PUAs), 2-trans,4-trans- decadienal, 2-trans,4-trans-octadienal, 2-trans,4-trans,7-octatrienal, 2-trans,4-trans-heptadienal, as well as tridecanal were tested on early and later larval development in the sea urchin Paracentrotus lividus. We also tested the effect of some of the more abundant diatom polyunsaturated fatty acids (PUFAs) on development, in particular 5,8,11,14,17-eicosapentaenoic acid (EPA), one of the main precursors of diatom PUAs, as well as 4,7,10,13,16,19- docosahexaenoic acid (DHA), 6,9,12,15-octadecatetraenoic acid (stearidonic acid), 6,9,12-octadecatrienoic acid (γ-linolenic acid) and 9,12-octadecadienoic acid (linoleic acid). PUAs blocked sea urchin cell cleavage in a dose dependent manner and with increasing chain length from C7 to C10 PUAs, with arrest occurring at 27.27 μM with heptadienal, 16.13 μM with octadienal, 11.47 μM with octatrienal and 5.26 μM with decadienal. Of the PUFAs tested, only EPA and stearidonic acid blocked cleavage, but at much higher concentrations compared to PUAs (331 μM for EPA and 181 μM for stearidonic acid). Sub-lethal concentrations of decadienal (1.32-5.26 μM) delayed development of embryos and larvae which showed various degrees of malformations depending on the concentrations tested. Sub-lethal concentrations also increased the proportion of TUNEL-positive cells indicating imminent death in embryos and larvae. Using decadienal as a model PUA, we show that this aldehyde can be detected spectrophotometrically for up to 14 days in f/2 medium.
