Showing papers by "Armando Córdova published in 2007"
TL;DR: In this paper, the ability of amino acids and amino acid derivatives to mediate various organocatalytic asymmetric transformations has been investigated and applied in the development of various reactions.
Abstract: The ability of amino acids and amino acid derivatives to mediate various organocatalytic asymmetric transformations has been investigated and applied in the development of various reactions. This work describes the development of a direct catalytic asymmetric α-aminomethylation of ketones and aldehydes, a catalytic asymmetric aziridination, hydrophosphination and amination of α,β-unsaturated aldehydes.
194 citations
TL;DR: The first direct organocatalytic asymmetric domino oxa-Michael/aldol condensation reaction is presented, which proceeds with high chemo- and enantioselectivities to give the corresponding chromene-3-carbaldehyde derivatives in high yields and with ee values of 83-98%.
Abstract: Catalytic enantioselective domino oxa-Michael/aldol condensations: asymmetric synthesis of benzopyran derivatives : -
190 citations
TL;DR: A highly chemo- and enantioselective organocatalytic cyclopropanation of aldehydes with bromomalonate and 2-bromoacetoacetate esters is presented and gives access to 2-formylcyclopropanes in high yields and up to 99?% ee.
Abstract: A highly chemo- and enantioselective organocatalytic cyclopropanation of ?,?-unsaturated aldehydes with bromomalonate and 2-bromoacetoacetate esters is presented. The reaction is catalyzed by chiral amines and gives access to 2-formylcyclopropanes in high yields and up to 99?% ee.
174 citations
TL;DR: Keeping it simple: Optically active phosphine derivatives can be obtained in high yields and in up to 99% ee by using simple chiral amines to catalyze the hydrophosphination of α,β-unsaturated alde aldehydes.
Abstract: Keeping it simple: Optically active phosphine derivatives can be obtained in high yields and in up to 99% ee by using simple chiral amines to catalyze the hydrophosphination of α,β-unsaturated alde ...
148 citations
TL;DR: The highly chemo- and enantioselective organocatalytic tandem reaction between N-protected hydroxyl amines and alpha,beta-unsaturated aldehydes is presented and provides access to 5-hydroxyisoxazolidines and beta-amino acids in high yields and with 90-99% ee.
136 citations
TL;DR: Secondary organic aerosols (SOA), produced by the transformation of organic gases in the atmosphere, have received a considerable amount of attention over the last three decades because of their ex... as discussed by the authors.
Abstract: Secondary Organic Aerosols (SOA), produced by the transformation of organic gases in the atmosphere, have received a considerable amount of attention over the last three decades because of their ex ...
110 citations
TL;DR: A highly enantioselective catalytic domino aza-Michael/aldol reaction: one-pot organocatalytic asymmetric synthesis of 1,2-dihydroquinolidines.
Abstract: A highly enantioselective catalytic domino aza-Michael/aldol reaction: one-pot organocatalytic asymmetric synthesis of 1,2-dihydroquinolidines
107 citations
TL;DR: Enantioselective organocatalytic conjugate addition of amines to alpha-beta-unsaturated aldehydes: one-pot asymmetric synthesis of beta-amino acids and 1,3-diamines.
100 citations
TL;DR: Organocatalytic asymmetric multi-component [C+NC+CC] synthesis of highly functionalized pyrrolidine derivatives was studied in this article, where the synthesis process was performed in an OCC environment.
97 citations
TL;DR: The highly enantioselective direct organocatalytic conjugate addition of aldehydes to maleimides is presented and its application in selective separation of Na6(CO3)2, Na2SO4, and Na2CO3 is described.
95 citations
TL;DR: The chiral amine catalyzed domino Michael/α-alkylation reaction gives access to functionalized cyclopentanones in good to high yields with 93 → 99% ee.
TL;DR: In this article, the highly chemo-and enanti-lective organocatalytic three-component reaction between N-arylhydroxylamines, aldehydes and?,?-unsaturated aldehyde is presented; the reaction gives access to isoxazolidines in high yields with >25:1 dr and 91-99% ee.
TL;DR: Highly enantioselective catalytic routes to Boc protected aza-Morita-Baylis-Hiliman-type products are presented and the organocatalytic asymmetric reactions between unmodified alpha,beta-unsaturated aza,Morita, Baylis and Hiliman types are presented.
TL;DR: In this article, the direct organocatalytic enantioselective epoxidation of α,β-unsaturated aldehydes with different peroxides is presented.
Abstract: The direct organocatalytic enantioselective epoxidation of α,β-unsaturated aldehydes with different peroxides is presented. Proline, chiral pyrrolidine derivatives, and amino acid-derived imidazolidinones catalyze the asymmetric epoxidation of α,β-unsaturated aldehydes. In particular, protected commercially available α,α-diphenyl- and α,α-di(β-naphthyl)-2-prolinols catalyze the asymmetric epoxidation reactions of α,β-unsaturated aldehydes with high diastereo- and enantioselectivities to furnish the corresponding 2-epoxy aldehydes in high yield with up to 97:3 dr and 98 % ee. The use of non-toxic catalysts, water and hydrogen peroxide, urea hydroperoxide or sodium percarbonate as the oxygen sources could make this reaction environmentally benign. In addition, one-pot direct organocatalytic asymmetric tandem epoxidation-Wittig reactions are described. The reactions were highly diastereo- and enantioselective and provide a rapid access to 2,4-diepoxy aldehydes. Moreover, a highly stereoselective one-pot organocatalytic asymmetric cascade epoxidation-Mannich reaction, which proceeds via the combination of iminium and enamine activation, is presented. The mechanism and stereochemistry of the amino acid- and chiral pyrrolidine-catalyzed direct asymmetric epoxidation of α,β-unsaturated aldehydes are also discussed.
TL;DR: In this paper, a simple diamine catalyzes the asymmetric Diels-Alder reaction with high stereoselectivity and furnishes the corresponding Diels−Alder adducts in good to high yields with >25:1 dr and up to 86% ee.
Abstract: The direct amine-catalyzed enantioselective Diels–Alder reaction between ?,?-unsaturated cyclic ketones and nitroolefins is presented. A simple diamine catalyzes the asymmetric Diels–Alder reaction with high stereoselectivity and furnishes the corresponding Diels–Alder adducts in good to high yields with >25:1 dr and up to 86?% ee. The study demonstrates a convenient entry to functionalized bicyclic molecules contaning four stereocenters that are formed with excellent diastreoselectivity and good to high enantioselectivity.
TL;DR: Highly enantioselective catalytic routes to Boc protected?-amino aldehydes, amino acids and amino alcohols are presented in this paper.
TL;DR: Organocatalytic asymmetric 5-hydroxypyrrolidine synthesis: a highly enantioselective route to 3-substituted proline derivatives.
TL;DR: In this article, the highly enantioselective organocatalytic α-selenenylation of aldehydes is presented, which gives access to α-phenylselenoaldehydes and β-selenoalcohols in high yields with up to >99% ee.
TL;DR: The ability of a primary amine containing acyclic beta(3)-amino acids to catalyze direct asymmetric anti-selective Mannich-type reactions is presented in this article.
Abstract: The ability of a primary amine containing acyclic beta(3)-amino acids to catalyze direct asymmetric anti-selective Mannich-type reactions is presented. The reactions are generally highly diastereo ...
TL;DR: The first catalytic asymmetric synthesis of tetrahydroxanthenones was presented in this paper, where simple organocatalytic enantioselective domino reactions between salicylic aldehyde derivatives and α,β-unsaturated cyclic ketones proceed with excellent chemoselectivity to give the corresponding TRSs in moderate to good yields and high enantiorelectivities.
TL;DR: The one-pot combination of amine and heterocyclic carbene catalysis (AHCC) enabled the synthesis of β-hydroxy, β-malonate and β-amino esters from α,β-unsaturated aldehydes with high enantioselectivity as mentioned in this paper.
TL;DR: The direct catalytic asymmetric α-aminomethylation of aldehydes is presented, which is a novel entry to valuable β2-amino acid derivatives.
Abstract: The direct catalytic asymmetric α-aminomethylation of aldehydes is presented. The chiral amine and amino acid catalyzed reactions between unmodified aldehydes and a formaldehyde-derived imine precursor were fast and proceeded with high chemo- and enantioselectivities. The corresponding dibenzyl-protected γ-amino alcohols were isolated in high yields with up to 98 % ee after in situ reduction. The reaction is a novel entry to valuable β2-amino acid derivatives.
TL;DR: Direct Bronsted acid-catalyzed derivatization of cellulose with poly(L-lactic acid) and D-mandelic acid was described in this paper.
Abstract: Direct Bronsted acid-catalyzed derivatization of cellulose with poly(L-lactic acid) and D-mandelic acid
TL;DR: In this article, a simple catalytic racemic synthesis of benzopyranes, benzothiopyranes and 1,2-dihydroquinolines is presented.
Abstract: A simple catalytic racemic synthesis of benzopyranes, benzothiopyranes and 1,2-dihydroquinolines is presented. The organocatalytic domino reactions between 2-heteroatom substituted aldehyde derivatives and ?,?-unsaturated aldehydes or ?,?-unsaturated cyclic ketones proceed with excellent chemoselectivity to give the corresponding products in good to high yields.
TL;DR: This work presents the first example of asymmetric amplification in the amino acid-catalyzed enantioselective synthesis of amino acid derivatives that provides support for a synergistic model for the evolution of homochirality by amino acid catalysis.
Abstract: The origins of biological homochirality have intrigued researchers since Pasteur’s discovery of the optical activity of biomolecules. Herein, we present the first example of asymmetric amplification in the amino acid-catalyzed enantioselective synthesis of amino acid derivatives that provides support for a synergistic model for the evolution of homochirality by amino acid catalysis.
TL;DR: In this article, the ability of amino acids and amino acid derivatives to mediate various organocatalytic asymmetric transformations has been investigated and applied in the development of various reactions.
Abstract: The ability of amino acids and amino acid derivatives to mediate various organocatalytic asymmetric transformations has been investigated and applied in the development of various reactions. This work describes the development of a direct catalytic asymmetric α-aminomethylation of ketones and aldehydes, a catalytic asymmetric aziridination, hydrophosphination and amination of α,β-unsaturated aldehydes.
TL;DR: The highly chemo- and enantioselective organocatalytic tandem reaction between N-carbamate-protected hydroxylamines and a,p-unsaturated aldehydes is presented and represents a unique entry for the asymmetric synthesis of 5-Hydroxyisoxazolidines, oxazolidin-5-ones or gamma-hydroxyamino alcohols in high yields and 90-99% ee.
Abstract: The highly chemo- and enantioselective organocatalytic tandem reaction between N-carbamate-protected hydroxylamines and a,p-unsaturated aldehydes is presented. The reaction represents a unique entry for the asymmetric synthesis of 5-hydroxyisoxazolidines, oxazolidin-5-ones or gamma-hydroxyamino alcohols in high yields and 90-99% ee. A procedure for the conversion of the oxazolidin-5-ones into the corresponding beta-amino acids is also described.
TL;DR: In this paper, Optically active phosphine derivatives can be obtained in high yields and in up to 99% ee by using simple chiral amines to catalyze the hydrophosphination of α,β-unsaturated alde...
Abstract: Keeping it simple: Optically active phosphine derivatives can be obtained in high yields and in up to 99% ee by using simple chiral amines to catalyze the hydrophosphination of α,β-unsaturated alde ...
TL;DR: In this article, the highly enantioselective direct organocatalytic conjugate addition of aldehydes to maleimides is presented, which is based on the approach described in this paper.
Abstract: The highly enantioselective direct organocatalytic conjugate addition of aldehydes to maleimides is presented.
TL;DR: In this article, ananti-selective organocatalytic conjugate addition of amines to alpha-beta-unsaturated aldehydes was proposed. But the amines were added to alpha and beta-uns saturated aldehyde.
Abstract: Enantioselective organocatalytic conjugate addition of amines to alpha-beta-unsaturated aldehydes: one-pot asymmetric synthesis of beta-amino acids and 1,3-diamines