Tethered Counterion-Directed Catalysis: Merging the Chiral Ion-Pairing and Bifunctional Ligand Strategies in Enantioselective Gold(I) Catalysis

Journal of the American Chemical Society, Journal Year: 2020, Volume and Issue: 142(8), P. 3797 - 3805

Published: Feb. 3, 2020

Tethering a metal complex to its phosphate counterion via phosphine ligand enables new strategy in asymmetric counteranion-directed catalysis (ACDC). A straightforward, scalable synthetic route gives access the gold(I) of displaying chiral phosphoric acid function. The generates catalytically active species with an unprecedented intramolecular relationship between cationic Au(I) center and counterion. benefits tethering two functions catalyst are demonstrated here tandem cycloisomerization/nucleophilic addition reaction, by attaining high enantioselectivity levels (up 97% ee) at unusually low 0.2 mol % loading. Remarkably, method is also compatible silver-free protocol.

Language: Английский

---

Yne–Enones Enable Diversity-Oriented Catalytic Cascade Reactions: A Rapid Assembly of Complexity

Accounts of Chemical Research, Journal Year: 2020, Volume and Issue: 53(10), P. 2358 - 2371

Published: Oct. 1, 2020

ConspectusA small-molecule collection with structural diversity and complexity is a prerequisite to using either drug candidates or chemical probes for discovery chemical–biology investigations, respectively. Over the past 12 years, we have engaged in developing efficient diversity-oriented cascade strategies synthesis of topologically diverse skeletons incorporating biologically relevant motifs such as O- N-heterocycles, fused polycycles, multifunctionalized allenes. In particular, highlighted use simple, linear, densely functionalized molecular platforms these reactions.This account details our efforts design novel metal- organo-catalyzed reactions, which include 2-(1-alknyl)-2-alken-1-ones (yne–enones) heterocyclization/cross-coupling cascades, heterocyclization/cycloaddition nucleophilic addition/cross-coupling addition/heterocyclization so on. Moreover, this Account outlines corresponding mechanistic insights, computational information, applications cascades construction various highly substituted carbo- heterocycles well acyclic compounds, e.g., allenes dienes. addition yne–enones, evolved functional groups original yne–enones provide series yne–enone variants, resulted products complementary reactivities.The reactivity profile defined by presence an alkyne moiety conjugated enone unit their mutual through-bond connectivity. Owing conceptually rapid development carbophilic activation, identified catalytic systems consisting metal catalysts, including Pd, Au, Rh complexes, catalysis, allowing unprecedented reactions be achieved through different-types reaction intermediates, all-carbon 1,n-dipoles, furan-based o-quinodimethanes (oQDMs), allenyl-metal species. commonly known transition-metal activity, Lewis acidity complexes crucial accomplish transformation. addition, enantioselective gold(I)-catalyzed variants were application bisphosphines (e.g., Cn-TunePhos), monophosphines, developed "Ming–Phos" chiral ligands. Importantly, Ming–Phos ligands exhibited excellent performance gold-catalyzed mechanistically distinct [3 + n]-cycloaddition sulfinamide possibly responsible interaction substrate control enantioselectivity. Subsequently, demonstrated that easily prepared polymer-supported ligand could applied heterogeneously asymmetric cycloaddition good stereocontrol. With metal-free divergent functionalization provides numerous synthetic outlets structure diversification. For example, are particularly attractive precursors achiral heterocycles, pyrazoles, isoxazoles, pyrroles, pyrans, etc.

Language: Английский

---

Pd/PC‐Phos‐Catalyzed Enantioselective Intermolecular Denitrogenative Cyclization of Benzotriazoles with Allenes and N‐Allenamides

Angewandte Chemie International Edition, Journal Year: 2019, Volume and Issue: 58(33), P. 11444 - 11448

Published: June 14, 2019

Abstract Reported herein is an asymmetric Pd/PC‐Phos‐catalyzed denitrogenative cyclization of benzotriazoles with allenes and N‐allenamides, representing the first example enantioselective cyclizations benzotriazoles. A series optically active 3‐methyleneindolines were obtained in good yields high ee values. The use inexpensive readily available starting materials, regio‐ enantioselectivity, a broad substrate scope, mild reaction conditions, no need for base, as well versatile functionalization make this approach attractive.

Language: Английский

---

Recent Advances in the Development of Chiral Gold Complexes for Catalytic Asymmetric Catalysis

Chemistry - An Asian Journal, Journal Year: 2021, Volume and Issue: 16(5), P. 364 - 377

Published: Jan. 2, 2021

Asymmetric gold catalysis has been rapidly developed in the past ten years. Breakthroughs have made by rational design and meticulous selection of chiral ligands. This review summarizes newly gold-catalyzed enantioselective organic transformations recent progress ligand (since 2016), organized according to different types ligands, including bisphosphine monophosphine phosphite-derived N-heterocyclic carbene ligands for asymmetric gold(I) as well heterocyclic oxazoline gold(III) catalysis.

Language: Английский

---

Asymmetric Dearomatization of Indole by Palladium/PC‐Phos‐Catalyzed Dynamic Kinetic Transformation

Angewandte Chemie International Edition, Journal Year: 2020, Volume and Issue: 59(49), P. 21991 - 21996

Published: Sept. 2, 2020

Abstract A palladium‐catalyzed intermolecular dynamic kinetic asymmetric dearomatization of 3‐arylindoles with internal alkynes was developed the use achiral Xantphos and chiral sulfinamide phosphine ligand ( PC‐Phos ) as co‐ligands. This method could deliver various spiro[indene‐1,3′‐indole] compounds in good yields (up to 95 % yield) up 98 ee . The salient features transformation include readily available substrates, ease scale‐up versatile functionalization products. mechanistic experiments gave some insights on active intermediates.

Language: Английский

---

Asymmetric gold catalysis enabled by specially designed ligands

Organic Chemistry Frontiers, Journal Year: 2024, Volume and Issue: 11(6), P. 1858 - 1895

Published: Jan. 1, 2024

This review is planned to provide a comprehensive overview of the progress made in design and development chiral ligands for asymmetric gold catalysis.

Language: Английский

---

Enantioselective Folding of Enynes by Gold(I) Catalysts with a Remote C₂-Chiral Element

Journal of the American Chemical Society, Journal Year: 2019, Volume and Issue: 141(30), P. 11858 - 11863

Published: July 10, 2019

Chiral gold(I) catalysts have been designed based on a modified JohnPhos ligand with distal C2-2,5-diarylpyrrolidine that creates tight binding cavity. The C2-chiral element is close to where the C–C bond formation takes place in cyclizations of 1,6-enynes. These chiral mononuclear applied for enantioselective 5-exo-dig and 6-endo-dig cyclization different 1,6-enynes as well first total synthesis three members carexane family natural products. Opposite enantioselectivities achieved seemingly analogous reactions 1,6-enynes, which result from folding substrates attractive aryl–aryl interactions.

Language: Английский

---

Enantioselective Gold(I)-Catalyzed Heterocyclization–Intermolecular Exo [4 + 3]-Cycloaddition Reactions for the Synthesis of Chiral Oxa-Bridged Benzocycloheptanes

Organic Letters, Journal Year: 2019, Volume and Issue: 21(9), P. 3018 - 3022

Published: April 17, 2019

The highly exo- and enantioselective gold-catalyzed tandem heterocyclization/[4 + 3] cycloaddition of 2-(1-alkynyl)-2-alken-1-ones 1,3-diphenylisobenzofuran was implemented by utilizing Ming-Phos, which provides a facile access to chiral seven-membered oxa-bridged rings in 80-98% yield with high exo selectivity ( exo/ endo up 50:1) 97% ee.

Language: Английский

---

New‐Generation Ligand Design for the Gold‐Catalyzed Asymmetric Activation of Alkynes

ChemPlusChem, Journal Year: 2021, Volume and Issue: 86(9), P. 1283 - 1296

Published: July 12, 2021

Abstract Gold(I) catalysts are ideal for the activation of alkynes under very mild conditions. However, unlike allenes or alkenes, triple bond cannot be prochiral. In addition, linear coordination displayed by gold(I) complexes places chiral ligand far away from substrate resulting in an inefficient transfer information. This poses a significant challenge achievement high enantiocontrol gold(I)‐catalyzed reactions alkynes. Although considerable progress on enantioselective transformations has recently been achieved, asymmetric non‐prochiral alkyne‐containing small molecules still represents great challenge. Herein we summarize recent advances intra‐ and intermolecular involving alkynes, discussing new designs that lie at basis these developments. We also focus mode action catalysts, their possible limitations towards next‐generation more efficient designs. Finally, square planar gold(III) complexes, which offer alternative to discussed.

Language: Английский

---

Enantioselective Alkoxycyclization of 1,6‐Enynes with Gold(I)‐Cavitands: Total Synthesis of Mafaicheenamine C

Angewandte Chemie International Edition, Journal Year: 2021, Volume and Issue: 60(17), P. 9339 - 9344

Published: Feb. 12, 2021

Chiral gold(I)-cavitand complexes have been developed for the enantioselective alkoxycyclization of 1,6-enynes. This cyclization has applied first total synthesis carbazole alkaloid (+)-mafaicheenamine C and its enantiomer, establishing configuration as R. The cavity effect was also evaluated in cycloisomerization dienynes. A combination experiments theoretical studies demonstrates that gold(I) forces enynes to adopt constrained conformations, which results high observed regio- stereoselectivities.

Language: Английский

---