Iridium‐Catalyzed Asymmetric Allylic Etherification and Ring‐Closing Metathesis Reaction for Enantioselective Synthesis of Chromene and 2,5‐Dihydrobenzo[b]oxepine Derivatives
TL;DR: Iridium-catalyzed asymmetric etherification of allylic carbonates with 2-vinylphenols and 2-allylphenols was realized in this paper.
Abstract: Iridium-catalyzed asymmetric etherifications of allylic carbonates with 2-vinylphenols and 2-allylphenols were realized. With a catalyst generated from 2 mol% of [Ir(cod)Cl]2 (cod=cycloocta-1,5-diene) and 4 mol% of the phosphoramidite ligand L2, the etherification products were obtained in excellent ees and then subjected to the ring-closing metathesis reaction providing an efficient synthesis of enantioenriched 2H-chromene and 2,5-dihydrobenzo[b]oxepine derivatives.
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TL;DR: In this review, an explicit outline of ligands, mechanism, scope of nucleophiles, and applications is presented, including ligand development, mechanistic understanding, substrate scope, and application in the synthesis of complex functional molecules.
Abstract: In this review, we summarize the origin and advancements of iridium-catalyzed asymmetric allylic substitution reactions during the past two decades. Since the first report in 1997, Ir-catalyzed asymmetric allylic substitution reactions have attracted intense attention due to their exceptionally high regio- and enantioselectivities. Ir-catalyzed asymmetric allylic substitution reactions have been significantly developed in recent years in many respects, including ligand development, mechanistic understanding, substrate scope, and application in the synthesis of complex functional molecules. In this review, an explicit outline of ligands, mechanism, scope of nucleophiles, and applications is presented.
434 citations
TL;DR: The plethora of methods developed for the catalytic asymmetric synthesis of enantioenriched allylic alcohols, including dynamic kinetic resolution (DKR/DKAT), nucleophilic 1,2-addition to carbonyl groups, allylic substitution, oxidation of C-H bonds, and the addition of O nucleophiles to π systems are summarized.
Abstract: Allylic alcohols represent an important and highly versatile class of chiral building blocks for organic synthesis. This Review summarizes the plethora of methods developed for the catalytic asymmetric synthesis of enantioenriched allylic alcohols. These include: dynamic kinetic resolution (DKR/DKAT), nucleophilic 1,2-addition to carbonyl groups, allylic substitution, oxidation of CH bonds, the addition of O nucleophiles to π systems, reduction of unsaturated carbonyl compounds, and an alternative route from enantioenriched propargylic alcohols. Furthermore, these catalytic asymmetric processes are exemplified by their applications in the syntheses of complex molecules such as natural products and potential therapeutic agents.
229 citations
TL;DR: This approach has not only realized the successful application of o-hydroxylstyrenes as oxa-diene precursors in catalytic asymmetric cycloadditions but also established a new cooperative catalytic system of chiral phosphoric acid and chiral guanidine.
Abstract: An enantioselective [4 + 2] cycloaddition of o-hydroxylstyrenes with azlactones has been established by merging chiral Bronsted acid (chiral phosphoric acid) and base (chiral guanidine) catalysis, which constructed a biologically important dihydrocoumarin scaffold in an efficient and enantioselective style (up to 99% yield, 96:4 er). This approach has not only realized the successful application of o-hydroxylstyrenes as oxa-diene precursors in catalytic asymmetric cycloadditions but also established a new cooperative catalytic system of chiral phosphoric acid and chiral guanidine.
89 citations
TL;DR: A ligand-directed metal-catalyzed asymmetric intermolecular hydroalkoxylation of alkoxyallene is reported and offers a new atom-efficient synthetic method toward various cyclic acetals with elaborate anomeric control.
Abstract: A ligand-directed metal-catalyzed asymmetric intermolecular hydroalkoxylation of alkoxyallene is reported. Combined with ring-closing-metathesis, this reaction offers a new atom-efficient synthetic method toward various cyclic acetals with elaborate anomeric control. Synthetic utility of the reaction was demonstrated by the atom-efficient and stereodivergent access to various mono- and disaccharides.
70 citations
TL;DR: In this paper, the Vielzahl an Methoden zur katalytischen asymmetrischen Synthese von enantiomerenangereicherten Allylalkohole zusammen is presented.
Abstract: Allylalkohole sind eine wichtige und uberaus nutzliche Klasse chiraler Bausteine fur die organische Synthese. Dieser Aufsatz fasst die Vielzahl an Methoden zur katalytischen asymmetrischen Synthese von enantiomerenangereicherten Allylalkoholen zusammen. Diese umfassen die dynamische kinetische Racematspaltung (DKR/DYKAT), 1,2-Additionen von Nucleophilen an Carbonylgruppen, allylische Substitutionen, Oxidationen von C-H-Bindungen, die Addition von O-Nucleophilen an π-Systeme, die Reduktion von ungesattigten Carbonylverbindungen und eine alternative Syntheseroute ausgehend von enantiomerenangereicherten Propargylalkoholen. Daruber hinaus wird der praparative Nutzen dieser katalytischen asymmetrischen Transformationen jeweils am Beispiel ihrer Anwendung in der Synthese komplexer Molekule wie z. B. Naturstoffen oder potenzieller Therapeutika gezeigt.
59 citations
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TL;DR: The focus of this review is on the area of enantioselective transition metal-catalyzed allylic alkylations which may involve C-C as well as C-X (X ) H or heteroatom) bond formation.
Abstract: Efficient and reliable amplification of chirality has borne its greatest fruit with transition metal-catalyzed reactions since enantiocontrol may often be imposed by replacing an achiral or chiral racemic ligand with one that is chiral and scalemic While the most thoroughly developed enantioselective transition metal-catalyzed reactions are those involving transfer of oxygen (epoxidation and dihydroxylation)1,2 and molecular hydrogen,3 the focus of this review is on the area of enantioselective transition metal-catalyzed allylic alkylations which may involve C-C as well as C-X (X ) H or heteroatom) bond formation4-9 The synthetic utility of transitionmetal-catalyzed allylic alkylations has been soundly demonstrated since its introduction nearly three decades ago10-21 In contrast to processes where the allyl moiety acts as the nucleophilic partner, we will limit our discussion to processes which result in nucleophilic displacements on allylic substrates (eq 1) Such reactions have been recorded with a broad
2,576 citations
TL;DR: Alkylations with Phenols, Nitrogen Nucleophiles in AAA Total Synthesis, and Considerations for Enantioselective Allylic Alkylation are presented.
Abstract: A. Primary Alcohols as Nucleophiles 2931 B. Carboxylates as Nucleophiles 2931 C. Alkylations with Phenols 2932 IV. Nitrogen Nucleophiles in AAA Total Synthesis 2935 A. Alkylamines as Nucleophiles 2935 B. Azides as a Nucleophile 2936 C. Sulfonamide Nucleophiles 2937 D. Imide Nucleophiles 2938 E. Heterocyclic Amine Nucleophiles 2940 V. Sulfur Nucleophiles 2941 VI. Summary and Conclusions 2941 VII. Acknowledgment 2941 VIII. References 2942 I. Considerations for Enantioselective Allylic Alkylation
2,230 citations
1,198 citations
TL;DR: Metal-catalyzed enantioselective allylation, which involves the substitution of allylic metal intermediates with a diverse range of different nucleophiles or S(N)2'-type allylic substitution, leads to the formation of C-H, -C, -O, -N, -S, and other bonds with very high levels of asymmetric induction.
Abstract: Metal-catalyzed enantioselective allylation, which involves the substitution of allylic metal intermediates with a diverse range of different nucleophiles or S(N)2'-type allylic substitution, leads to the formation of C-H, -C, -O, -N, -S, and other bonds with very high levels of asymmetric induction. The reaction may tolerate a broad range of functional groups and has been applied successfully to the synthesis of many natural products and new chiral compounds.
1,134 citations
TL;DR: This paper presents a meta-analyses of the chiral stationary phase of Na6(CO3(SO4)(SO4)2, where Na2SO4 is a major component of the polymethine of carbon dioxide and its opposite, Na2CO3, which has an important role in the formation of DNA.
Abstract: Departament of Organic Chemistry, University of Geneva, 30 Quai Ernest Ansermet, 1211 Geneve 4, Switzerland, Department of Organic Chemistry, Stockholm University, Arrhenius Laboratoriet, 106 91 Stockholm, Sweden, Organic Chemistry II, Dormund University of Technology, Otto-Hahn-Strasse 6, D-44227 Dortmund, Germany, and Departament de Quimica Fisica i Inorganica, Universitat Rovira i Virgili, C/ Marcel · li Domingo s/n, 43007 Tarragona, Spain
832 citations