Showing papers by "Víctor S. Martín published in 2016"
TL;DR: Gallic acid efficiently catalyses radical arylations in water-acetone at room temperature and constitutes a greener alternative to arylation, and also unleashes an alternative method for the reutilisation of bio-wastes.
42 citations
TL;DR: A highly efficient, diastereoselective, iron(III)-catalyzed intramolecular hydroamination/cyclization reaction involving α-substituted amino alkenes is described and an enantiodivergent approach to the synthesis of both (+)- and (-)-pyrrolidine 197B alkaloids from l-glutamic acid is highlighted.
Abstract: A highly efficient, diastereoselective, iron(III)-catalyzed intramolecular hydroamination/cyclization reaction involving α-substituted amino alkenes is described. Thus, enantiopure trans-2,5-disubstituted pyrrolidines and trans-5-substituted proline derivatives were synthesized by means of a combination of enantiopure starting materials, easily available from l-α-amino acids, with sustainable metal catalysts such as iron(III) salts. The scope of this methodology is highlighted in an enantiodivergent approach to the synthesis of both (+)- and (-)-pyrrolidine 197B alkaloids from l-glutamic acid. In addition, a computational study was carried out to gain insight into the complete diastereoselectivity of the transformation.
19 citations
TL;DR: Gallic acid converts atmospheric oxygen into hydrogen peroxide, which is able to oxidize arylboronic acids as a proof of concept of sustainable oxidations as discussed by the authors, and tannic acid and grape pomace extract are also able to perform oxidations with air.
15 citations
TL;DR: Key substrates β,γ-unsaturated N-acyloxazolidin-2-ones were subjected to an "Evans Aldol-Prins" protocol to generate five σ-bonds and five stereocenters in only a one-pot process with yields up to 60% and excellent stereoselectivities.
6 citations
TL;DR: An improved protocol for the synthesis of enantiomerically pure allylic amines is reported, which circumvents the problem of instability of the aldehydes and tolerates well both Wittig and Horner–Wadsworth–Emmons organophosphorus reagents.
Abstract: An improved protocol for the synthesis of enantiomerically pure allylic amines is reported. N-Protected α-amino esters derived from natural amino acids were submitted to a one-pot tandem reduction-olefination process. The sequential reduction with DIBAL-H at -78 °C and subsequent in situ addition of organophosphorus reagents yielded the corresponding allylic amines without the need to isolate the intermediate aldehyde. This circumvents the problem of instability of the aldehydes. The method tolerates well both Wittig and Horner-Wadsworth-Emmons organophosphorus reagents. A better Z-(dia)stereoselectivity was observed when compared to the previous one-pot method. The (dia)stereoselectivity of the process was affected neither by the reaction solvent nor by the amount of DIBAL-H employed. The method is compatible with the presence of free hydroxy groups as shown with serine and threonine derivatives.
1 citations
TL;DR: The first total synthesis of the bioactive natural product 2,6-(E,E)-thymifodioic acid, also called incanic acid, and its stereoisomers is described in this paper.
1 citations
TL;DR: The Evans Aldol-Prins reaction of β,γ-unsaturated N-aryloxazolidin-2-ones with a variety of aldehydes offers a general and stereoselective synthesis of highly substituted tetrahydropyrans.
Abstract: Evans Aldol—Prins reaction of β,γ-unsaturated N-aryloxazolidin-2-ones with a variety of aldehydes offers a general and stereoselective synthesis of highly substituted tetrahydropyrans.
1 citations
TL;DR: In this article, an improved protocol for the synthesis of enantiomerically pure allylic amines was reported, where N-Protected α-amino esters derived from natural amino acids were submitted to a one-pot tandem reduction-olefination process.
Abstract: An improved protocol for the synthesis of enantiomerically pure allylic amines is reported. N-Protected α-amino esters derived from natural amino acids were submitted to a one-pot tandem reduction-olefination process. The sequential reduction with DIBAL-H at -78 °C and subsequent in situ addition of organophosphorus reagents yielded the corresponding allylic amines without the need to isolate the intermediate aldehyde. This circumvents the problem of instability of the aldehydes. The method tolerates well both Wittig and Horner-Wadsworth-Emmons organophosphorus reagents. A better Z-(dia)stereoselectivity was observed when compared to the previous one-pot method. The (dia)stereoselectivity of the process was affected neither by the reaction solvent nor by the amount of DIBAL-H employed. The method is compatible with the presence of free hydroxy groups as shown with serine and threonine derivatives.
01 Nov 2016
TL;DR: The development of first systematic study for the generation of a small library of dibenzo[b,e]oxepin-11(6H)-ones by direct intramolecular acylation from readily available 2-(phenoxymethyl)benzoic acids is described.
Abstract: Helminthiasis is a serious problem worldwide resulting in high human morbidity and enormous economic losses in livestock, especially in tropical and sub-tropical countries. Anthelmintic drugs are used for the control of parasitic infections caused by helminths. Resistance to current anthelmintics has prompted the search for new drugs. In this context, the tricyclic dibenzo[b,e]oxepin-11(6H)-one scaffold emerges as an interesting synthetic target because a large number of compounds having this privileged structure present relevant biological activities; such as antidepressant, anxiolytic, antipsychotic, antitumor, and anti-inflammatory properties.
Herein, we describe the development of first systematic study for the generation of a small library of dibenzo[b,e]oxepin-11(6H)-ones by direct intramolecular acylation from readily available 2-(phenoxymethyl)benzoic acids. For this purpose, a novel and efficient cooperative system consisting of SnCl2 and Cl2CHOCH3 (DCME) is presented. This new methodology show be compatible with a wide variety of functional groups in good to excellent yields and high regioselectivity. The generality of present protocol was applied to the scalable and reproducible synthesis of tricyclic antidepressant doxepin. The synthesized dibenzo[b,e]oxepinones were evaluated for their biological activity using the free-living nematode Caenorhabditis elegans as effective and cost-efficient model system for anthelmintic discovery.