Narciso Martín Garrido

Universidad de Salamanca · Department of Organic Chemistry

The preparation and characterization of a new chiral tertiary dibenzylamine are described. These molecules are well known in the literature for their high neuropharmacological potential. The general synthetic pathway is based on asymmetric Aza–Michael addition of chiral (R)-N-benzyl-N-(α-methylbenzyl)amide to methyl cyclohex-1-en-carboxilate obtain...

A concise review covering updated presence and role of 2-phenethylamines in medicinal chemistry is presented. Open-chain, flexible alicyclic amine derivatives of this motif are enumerated in key therapeutic targets, listing medicinal chemistry hits and appealing screening compounds. Latest reports in discovering new bioactive 2-phenethylamines by r...

(S)-N1,N3-dibenzyl-1-cyclohexyl-N1,N3-bis((R)-1-phenylethyl)propane-1,3-diamine was prepared in good yield by the reduction of the corresponding amide, which was obtained by the addition of a chiral lithium amide to an α,β-unsaturated ester. The target compound was fully characterized by NMR (1H and 13C), high-resolution mass spectrometry and polar...

Ezetimibe is a well-known drug that lowers blood cholesterol levels by reducing its absorption in the small intestine when joining to Niemann-Pick C1-like protein (NPC1L1). A ligand-based study on ezetimibe analogues is reported, together with one-hit synthesis, highlighted in the study. A convenient asymmetric synthesis of (2S,3S)-N-α-(R)-methylbe...

In synthetic organic chemistry, there are very useful basic compounds known as building blocks. One of the main reactions wherein they are applied for the synthesis of complex molecules is the Diels–Alder cycloaddition. This reaction is between a diene and a dienophile. Among the most important dienes are the cyclic dienes, as they facilitate the r...

The asymmetric synthesis of a compound with the cyclopentan[c]pyran core of iridoid natural products in four steps and 40% overall yield is reported. Our methodology includes a one-pot tandem domino reaction which provides a trisubstituted cyclopentane with five new completely determined stereocenters, which were determined through 2D homo and hete...

The 1,3-dipolar cycloaddition of a chiral nitrone with α,β-unsaturated lactones was carried out to give the corresponding isoxazolidines. Tetrahydro-1,3-oxazines with an oxa-tropane skeleton were obtained in one step by alkylation. The structures of several of these compounds were corroborated by X-ray diffraction and molecular modelling studies co...

A convenient asymmetric synthesis of methyl (2S,3S,6R)-6-(4-fluorophenyl)-2-(4-hydroxyphenyl)-piperidine-3-carboxylate is described, starting from Baylis–Hillman adducts. The route involves a domino process: allylic acetate rearrangement, stereoselective Ireland–Claisen rearrangement and asymmetric Michael addition, which provides a δ-amino acid de...

The synthesis of the two 7,8-epoxides of carvone has been attained using organocatalysis in a two-step synthetic route through a bromoester intermediate. Among the different reaction conditions tested for the bromination reaction, moderate yields and diastereoselection are achieved using proline, quinidine, and diphenylprolinol, yielding the corres...

A novel 1,4-Phenyl radical rearrangement (1,4-PhRR) is described in a typical Barton decarboxylation procedure. While carrying out this reaction in presence of a N,N-disubstituted β-amino acid derivative, the decarboxyphenyl rearranged derivative is obtained, as well as in presence of β-N,N-acylamide. On the other hand, secondary amines give the β-...

Organocatalysis constitutes one of the main research areas in organic chemistry from the last two decades. This chemistry has been applied to the synthesis of many natural products and structures in a manner that reduces the residues and so the ecological impact. In this review, we consider the work that has been done for the synthesis of bicyclo[3...

A novel approach to the production of chiral 1,3-cyclohexadienals has been developed. The organocatalysed asymmetric reaction of different β-disubstituted-α,β-unsaturated aldehydes with a chiral α,β-unsaturated aldehyde in the presence of a Jørgensen-Hayashi organocatalyst provides easy and stereocontrolled access to the cyclohexadienal backbone. T...

Experimental procedure for the synthesis of α,β-aldehyde intermediates. (DOCX)

X-Ray crystallographic data. (DOCX)

The asymmetric synthesis of methyl (E)-4-((1. R,2. S,3. R)-3-amino-2-((E)-2-methoxycarbonyl-eten-1-yl)cyclohexyl)but-2-enoate 14 has been achieved from dimethyl (2. E,7. E)-nona-2,7-dienedioate 2. A key step is the asymmetric synthesis of 1-hydroxyoctahydro-1. H-isochromene derivative 5 whose X-ray analysis corroborated the stereochemistry of the n...

The title compound, C 22 H 25 NO 5 , was prepared by CAN [cerium(IV) ammonium nitrate] oxidation of the corresponding β-lactam. The dihedral angle between the benzene rings is 13.3 (4)° and the C—N—C(=O)—C torsion angle is 176.1 (6)°. In the crystal, amide- C (4) N—H...O and reinforcing C—H...O hydrogen bonds link the molecules into infinite [010]...

The title compound, C12H15NO3S, was prepared by 1,3-dipolar cyclo-addition of 3,4-di-hydro-2H-pyrrole 1-oxide and phenyl vinyl sulfone. In the mol-ecule, both fused five-membered rings display a twisted conformation. In the crystal, C-H⋯O hydrogen bonds link neighbouring mol-ecules, forming chains running parallel to the b axis.

Structure-Activity Relationship (SAR) is a current approach in the design of new pharmacological agents. We previously reported the synthesis of a novel analogue of morphine, a 2-azabicyclo[3.3.1]nonane, which contains a β-amino acid. This bicyclic core exhibits two distinctive chemical handles for further elaboration, which allowed us to create a...

The first organocatalytic synthesis of cis-decalins using sulfonyl Nazarov reagents is reported. The Jørgensen's catalyst directs this highly enantioselective synthesis using different cyclohexenal derivatives.

The asymmetric Aza-Michael addition of homochiral lithium benzylamides to α,β-unsaturated esters represents an extended protocol to obtain enantioenriched β-amino esters. An exhaustive mechanistic revision of the originally proposed mechanism is reported, developing a quantum mechanics/molecular mechanics protocol for the asymmetric Aza-Michael rea...

Different quick synthetic procedures are described in the elaboration of flexible PNA monomers based on the 6-amino-8-base-octanoate and 5-amino-7-base-heptanoate scaffolds. Asymmetric Aza-Michael monoaddition is successfully applied to affordable starting materials derived from sebacic/azelaic long-chain diacids and 6-membered oxacyclohexane comme...

Isatin and its derivatives have been widely studied due to their biological activities. Recently there has been a renewed interest in the synthesis of new derivatives by use of organocatalysts. This review deals with this area.

Isatin and its derivatives have been widely studied due to their biological activities. Recently there has been a renewed interest in the synthesis of new derivatives by use of organocatalysts. This review deals with this area.

Polyhydroxylated pyrrolidines have been synthetized in a one pot procedure by addition of an organometallic reagent to isoxazolidines obtained in turn by a 1,3-dipolar cycloaddition between nitrones and vinylsulfones. This method highlights sulfone reactivity and opens an easy way to prepare chiral pyrrolidines by cyclic imines as key intermediates...

A convenient asymmetric synthesis of (1R,5R,9R)-2-azabicyclo[3.3.1]nonane-9-carboxylic acid is described, starting from (2E,7E)-dimethyl nonadienedioate. The route involves a stereoselective domino Michael-Dieckman process that furnishes a 1,2,3-trisubstituted cyclohexane derivative bearing three adjacent stereocenters with full stereochemical cont...

A novel approach for the synthesis of chiral tetrasubstituted pyrrolidines has been developed. The rearrangement of isoxazolidines into tetrahydro-1,3-oxazines using reactive organic bromides is herein described for the first time. The subsequent opening reaction of these tetrahydro-1,3-oxazines with nucleophiles probes the usefulness of the method...

The title compound, C(14)H(19)NO(5)S, was prepared by nucleophilic addition of the lithium derivative of methyl-phenyl-sulfone to (3S,4R)-3,4-isopropyl-idene-dioxy-pyrroline 1-oxide. There are four mol-ecules in the asymmetric unit. The crystal structure determination confirms the configuration of the chiral centres as 2R,3S,4R. In the crystal, pai...

The title compound, C(13)H(18)Br(2)O(3), was prepared by a bromination reaction of (1E,3Z)-methyl 5-oxocyclo-octa-1,3-diene-carboxyl-ate, which was obtained by an ep-oxy-dation reaction of tert-butyl cyclo-oct-1,3-diene-carboxyl-ate. The crystal structure confirms unequivocally the absolute configuration of both chiral centres to be S. In the cryst...

The addition of three nitrones to phenylvinylsulfone, 1, has been studied. The stereochemistry previously established by two-dimensional NMR techniques was confirmed by X-ray crystal structure determination. Theoretical studies made us propose that this reaction is not purely regioselective, but by controlling the substituents of nitrone and temper...

This paper describes a full conformational and stereochemical study of bicylo[3.3.1]nonanes, obtained from the reaction between cinnamaldehyde and 1-morpholine 1-cyclohexene. NMR data and stereochemistry were unequivocally established and assigned by two-dimensional experiments and single-crystal X-ray analysis. The crystal structure of a minor com...

(5R,6S,E)-5-Alkyl-2-(2-(methoxymethoxy)ethylidene)-6-(phenylsulfonyl)cyclohex-3-enones, have been obtained by a domino reaction using tandem catalysis with a Nazarov reagent 3, and several unsaturated aldehydes.

The synthesis of a C-branched homopyrrolidinol has been achieved by making use of the reactivity of the sulfone group in four different ways. The stereochemistry of the two compounds has been established by X-ray diffraction analysis.

The title compound, C(14)H(17)NO(5)S, was prepared by oxidation of (2R,3S,4R)-2-phenyl-sulfonyl-methyl-1-hy-droxy-3,4-iso-pro-pyl-idene-dioxy-pyrrolidine. Its crystal structure confirms unequivocally its configuration. Two inter-molecular C-H⋯O inter-actions help to establish the packing.

The title compound C(7)H(11)NO(3) was prepared by intra-molecular nucleophilic displacement of 2,3-O-iso-propyl-idene-d-erythronolactol. There are two mol-ecules in the asymmetric unit, which are related by a pseudo-inversion centre. The crystal structure determination confirms unequivocally the configuration of the chiral centres as 3S,4R. In the...

An enantioselective synthesis of (2S,3R)-piperidine-2,3-dicarboxylic acid and (2S,3S)-piperidine-2,3-dicarboxylic acid is described. This synthesis was mainly based on a δ-amino acid formation via a domino reaction: allylic acetate rearrangement, stereoselective Ireland-Claisen rearrangement and asymmetric Michael addition protocol from a Baylis–Hi...

A novel prolinol-derived organocatalyst (DBEP) is prepared and applied to the asymmetric Michael addition of β-nitrostyrenes (II) towards cyclohexanone (I).

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

The reactivity of sulfonylbutadienes has been studied with enamines and the obtained products used as starting materials for the synthesis of Ginsenol analogues.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

The reaction of bicyclic ditetpenes either with an allylic grouping ot an equivalent function on ring B afforded a simple and rapid synthesis of tetrahydronaphthalenic diterpenes of the isofregenedmae type.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

This paper describes an anomalous behaviour of the Sharpless dihydroxylation of a terminal olefin. The synthesis of a new chiral pyrrolidine and its application as an organocatalyst in the Michael addition of cyclohexanone into nitrostyrenes are described.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

A convenient, asymmetric synthesis of (R)-homopipecolic acid methyl ester and an homochiral peptide nucleic acid (PNA) monomer building block are described, starting from the orthogonally disubstituted (2E,7E)-nonadienedioate. The approach involves stereoselective Michael monoaddition of (R)-N-benzyl-N-alpha-methylbenzylamide to the unsaturated est...

The synthesis of a new chiral pyrrolidine has been performed using 2,3-O-isopropylidene-D-erythronolactol as a suitable starting material.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

An efficient asymmetric synthesis of (+)-L-733,060, (-)(2S,3R)-1 and (+)-CP-99,994, starting from a Baylis-Hillman adduct, is described. The key steps include a novel domino reaction: stereoselective Ireland-Claisen rearrangement, asymmetric Michael addition, and piperidone ring formation through a one-pot reaction hydrogenolysis/lactamization and...

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

A highly efficient asymmetric synthesis of (1S,2R)-2-aminocyclooctanecarboxylic acid has been completed. This asymmetric synthesis using cycloocta-1,5-diene as the starting material is achieved in 77% yield via a four-step sequence from tert-butyl cycloocta-1,7-dienecarboxylate 10 where the extra double bond adjacent to the unsaturated ester is ess...

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

A new, easily tunable organocatalyst has been synthesized and applied in the Michael reaction of cyclohexanones to nitrostyrenes.

This paper focuses on the latest developments in asymmetric epoxidation of electron-deficient olefins since the review by Porter and Skidmore on chiral ligand-metal peroxide systems, polyamino acid catalysed and organocatalysed epoxidations. Particular attention has been paid to the most recent advances using chiral pyrrolidines as organocatalysts.

A novel domino reaction--stereoselective Ireland-Claisen rearrangement and asymmetric Michael addition--is described. A protocol starting from Baylis-Hillman adducts 3a-f using chiral lithium amide affords optically active gamma-substituted delta-amino acids 4a-f with high diastereoselectivities and enantioselectivities. The acid can be isolated ea...

Acetone and diazotized anthranilic acid react in alkaline solution, giving a fluorescent intermediate that can be measured at excitation and emission wavelengths of 305 and 395 nm, respectively. Based on this, a fluorimetric flow-injection method is proposed for the determination of acetone in aqueous solution. Under the proposed conditions, aceton...

A new chiral organocatalyst is described in this paper. A new mechanism for the overall Michael condensation of ketones with nitroolefins using our catalyst is suggested based on molecular modelling studies.

Secondary homochiral lithium amides derived from α-methylbenzylamine undergo highly diastereoselective conjugate additions to a range of α,β-unsaturated esters. The corresponding β-amino acids are readily liberated by successive N-debenzylation and ester hydrolysis, furnishing (R)-β-amino butyric acid, (R)-β-amino pentanoic acid, (S)-β-leucine, (R)...

Cyclopropanols have found an increasing number of uses as synthetic intermediates and as functional groups in the design of enzyme inhibitors. This mini-review will discuss some of the most recent and successful methodologies for the synthesis of these entities, focusing mainly on the stereoselective transformations. The new procedure developed in...

An expeditious asymmetric synthesis of pent-3-yl (R)-6-methyl-cyclohex-1-enecarboxylate has been achieved in four steps in 42% overall yield employing as the key step a domino reaction initiated by a highly diastereoselective lithium amide 1,4-conjugate addition to a nona-2,7-diendioic diester followed by a 6-exo-trig cyclisation of the thus formed...

A new synthesis of chiral alkyl pyrroles and pyrrolines has been achieved in an easy straightforward way, using the addition of organometallics to chiral imines.

The total synthesis of ent-sachalinol A, has been achieved by utilizing a Sharpless epoxidation and nitrile substitution as the key reactions.

The rearrangement under oxidative conditions of 3-(benzyloxy)-tetrahydro- 2,6,6-trimethyl-2H-pyran-2-carbaldehydes to afford a chiral protected tetrahydrofuran lactol is described.

We report the asymmetric synthesis of di-3-pentyl (3S,alphaS,7E)-3-N-benzyl-N-alpha-methylbenzylamino-dec-7-enedioate (9), which contains the correct functionalization to produce delta-amino acid derivatives to be used as monomers for Peptide Nucleic Acid (PNA) formation With this aim, thymine-pentanoic acid 15 and some of its ester derivatives wer...

A study of the addition of vinylsulfones versus alkylsufones has been done, and applied to the synthesis of N-(tert-butoxycarbonyl)-l-homophenylalanine.

Several precursors of unnatural amino acids have been synthesized by addition of vinyl sulfones to an imine derived from (R)-glyceraldehyde. In these reactions the addition not only takes place in a stereoselective way, but a hydride transfer is also produced giving rise to the saturated sulfones and a new imine.

A chiral pyrrolidinopyridine was synthesized by using Buchwald methodology. The sulfone was used to add a benzyl group, which positioned a phenyl near the reacting position.

A new methodology for the synthesis of polyhydroxylated pyrrolidines using epoxysulfones is described. The synthesis of two natural glycosidase inhibitors, 1,4-dideoxy-1,4-imino-d-lyxitol and 1,4-dideoxy-1,4-imino-d-mannitol (DIM), is reported.

The product distribution upon conjugate addition of homochiral lithium N-benzyl-N-alpha-methylbenzylamide to dimethyl-(E,E)-nona-2,7-dienedioate can be controlled to give either the cyclic 1,2-anti-1,6-anti-beta-amino ester (derived from conjugate addition and intramolecular enolate cyclisation) or the acyclic bis-beta-amino ester derivative (deriv...

A totally different approach to conformationally restricted glutamic acid analogues is described, in which one of the acid functions is replaced by a cyclopropanol. The reactivity of cyclopropanol vinyl sulfones toward addition of lithiated Schöllkopf bislactim ether provides a facile synthesis of α-amino acid diastereoisomers. Conformational analy...

A new methodology for the synthesis of N-diphenylmethylene-2-vinyl-substituted cyclopropylamines, starting from the allylsulfone 11, is described. The starting material 11 can be obtained in both enantiomeric forms. The stereoselectivity of the cyclopropane formation has been studied by molecular modeling

The stereoisomers of 2-amino-5-carboxymethyl-cyclopentane-1-carboxylate may be prepared stereoselectively from diester derivatives of (E,E)-octa-2,6-diendioc acid, with the key step utilising the conjugate addition of homochiral lithium N-benzyl-N- alpha-methylbenzylamide. The trans-C(1)-C(2)-stereoisomers are readily prepared via a diastereoselect...

For Abstract see ChemInform Abstract in Full Text.

A method to synthesize chiral 2,3,4-trisusbtituted tetrahydrothiophenes in both enantiomerically pure forms starting from 1-hydroxymethyl-4-phenylsulfonylbutadiene is described.

The asymmetric synthesis of the orthogonally funtionalised compounds tert-butyl 2-N-benzyl-N-alpha-methylbenzylamino-5-methoxycarbonylmethylcyclopentane- 1-carboxylate and methyl 2-N-benzyl-N-alpha-methylbenzylamino-5-carboxymethylcyclo- pentane-1-carboxylate by a domino reaction of tert-butyl methyl (E,E)-octa-2,6- diendioate with lithium N-alpha-...

[reaction: see text] Several chiral building blocks have been obtained easily in large quantities from an epoxysulfone (9) that could be obtained in both enantiomeric forms from accessible starting materials.