Bond-Forming and -Breaking Reactions at Sulfur(IV): Sulfoxides, Sulfonium Salts, Sulfur Ylides, and Sulfinate Salts

Chemical Reviews, Journal Year: 2019, Volume and Issue: 119(14), P. 8701 - 8780

Published: June 25, 2019

Organosulfur compounds have long played a vital role in organic chemistry and the development of novel chemical structures architectures. Prominent among these organosulfur are those involving sulfur(IV) center, which been subject countless investigations over more than hundred years. In addition to list textbook sulfur-based reactions, there has sustained interest organosulfur(IV) recent Of particular within is ease with synthetic chemist can effect wide range transformations through either bond formation or cleavage at sulfur. This review aims cover developments past decade molecules provide insight into both reactions critically rely on this versatile element diverse scaffolds that thereby be synthesized.

Language: Английский

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Stereoselective amino acid synthesis by synergistic photoredox-pyridoxal radical biocatalysis

Science, Journal Year: 2023, Volume and Issue: 381(6656), P. 444 - 451

Published: July 27, 2023

Developing synthetically useful enzymatic reactions that are not known in biochemistry and organic chemistry is an important challenge biocatalysis. Through the synergistic merger of photoredox catalysis pyridoxal 5'-phosphate (PLP) biocatalysis, we developed a radical biocatalysis approach to prepare valuable noncanonical amino acids, including those bearing stereochemical dyad or triad, without need for protecting groups. Using engineered PLP enzymes, either enantiomeric product could be produced biocatalyst-controlled fashion. Synergistic

Language: Английский

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Recent updates and future perspectives in aziridine synthesis and reactivity

Chem, Journal Year: 2023, Volume and Issue: 9(7), P. 1658 - 1701

Published: May 11, 2023

Language: Английский

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Stereodivergent assembly of tetrahydro-γ-carbolines via synergistic catalytic asymmetric cascade reaction

Nature Communications, Journal Year: 2019, Volume and Issue: 10(1)

Published: Dec. 5, 2019

Abstract Enantiomerically enriched indole-containing heterocycles play a vital role in bioscience, medicine, and chemistry. As one of the most attractive subtypes indole alkaloids, highly substituted tetrahydro-γ-carbolines are basic structural unit many natural products pharmaceuticals. However, syntheses with high functionalities from readily available reagents significant challenging. In particular, stereodivergent containing multi-stereogenic centers remain quite difficult. Herein, we report an expedient assembly remarkably levels stereoselective control efficient cascade process aldimine esters indolyl allylic carbonates via synergistic Cu/Ir catalyst system. Control experiments-guided optimization catalysts mechanistic investigations reveal that allylation reaction subsequent iso -Pictet-Spengler cyclization key elements to success.

Language: Английский

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Synthesis of BCP Benzylamines From 2‐Azaallyl Anions and [1.1.1]Propellane

Angewandte Chemie International Edition, Journal Year: 2018, Volume and Issue: 57(48), P. 15857 - 15861

Published: Oct. 6, 2018

For bioactive molecules, bicyclo[1.1.1]pentanes (BCPs) are an emerging isostere of rigid spacer groups that have shown potential to improve drug-like qualities. As BCPs become increasingly popular motif for evaluation in drug candidates, organic chemists must meet the demand reliably incorporate them into new targets. To provide access BCP analogues diaryl methanamines, a ubiquitous scaffold medicinal chemistry, we report synthesis benzylamines through reactivity [1.1.1]propellane with 2-azaallyl anions, which generated situ from N-benzyl ketimines. The reaction proceeds rapidly at room temperature and tolerates broad substrate scope, providing straightforward 23 benzylamine derivatives. Initial experiments support intermediacy anion. Additionally, can be promoted by substoichiometric loadings base, highlighting unusual both 2-azaallyls [1.1.1]propellane.

Language: Английский

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Palladium‐Catalyzed Defluorinative Alkylation of gem‐Difluorocyclopropanes: Switching Regioselectivity via Simple Hydrazones

Angewandte Chemie International Edition, Journal Year: 2021, Volume and Issue: 60(23), P. 13098 - 13104

Published: March 23, 2021

Abstract Conventional approaches for Pd‐catalyzed ring‐opening cross‐couplings of gem ‐difluorocyclopropanes with nucleophiles predominantly deliver the β‐fluoroalkene scaffolds (linear selectivity). Herein, we report a cooperative strategy that can completely switch reaction selectivity to give alkylated α‐fluoroalkene skeletons (branched The unique reactivity hydrazones enables analogous inner‐sphere 3,3′‐reductive elimination driven by denitrogenation, as well assistance steric‐embedded N ‐heterocyclic carbene ligand, are key regioselectivity. A wide range derived from naturally abundant aryl and alkyl aldehydes applicable, various ‐difluorocyclopropanes, including modified pharmaceutical biological molecules, be efficiently functionalized high value α‐fluorinated alkene motifs under mild conditions.

Language: Английский

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Photoredox-Catalyzed Deaminative Alkylation via C–N Bond Activation of Primary Amines

Journal of the American Chemical Society, Journal Year: 2020, Volume and Issue: 142(43), P. 18310 - 18316

Published: Oct. 15, 2020

Primary amines are often cheap, naturally occurring, and chemically diverse starting materials. For these reasons, deaminative functionalization of has emerged as an important area research. Recent advances in C-N activation transform simple α-1° α-2° into alkylating reagents via Katritzky pyridinium salts. We report a complementary method that activates sterically encumbered α-3° primary through visible light photoredox catalysis. By condensing with electron-rich aryl aldehyde, we enable oxidation deprotonation event, which generates key imidoyl radical intermediate. A subsequent β-scission event liberates alkyl radicals for coupling electron-deficient olefins the generation unnatural γ-quaternary amino acids other valuable synthetic targets.

Language: Английский

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Amino Acid Schiff Base Bearing Benzophenone Imine As a Platform for Highly Congested Unnatural α-Amino Acid Synthesis

Journal of the American Chemical Society, Journal Year: 2020, Volume and Issue: 142(18), P. 8498 - 8505

Published: April 22, 2020

Unnatural α-amino acids are invaluable building blocks in synthetic organic chemistry and could upgrade the function of peptides. We developed a new mode for catalytic activation amino acid Schiff bases, serving as platform highly congested unnatural synthesis. The redox active copper catalyst enabled efficient cross-coupling to construct contiguous tetrasubstituted carbon centers. broad functional group compatibility highlights mildness present catalysis. Notably, we achieved successive β-functionalization oxidation bases afford dehydroalanine derivatives bearing carbon. A three-component reaction an base, alkyl bromides, styrene demonstrated high utility method. diastereoselective was also using menthol chiral auxiliary, delivering enantiomerically enriched α,β-continuous synthesized be derivatized incorporated into peptide

Language: Английский

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Silver-Catalyzed [3 + 3] Dipolar Cycloaddition of Trifluorodiazoethane and Glycine Imines: Access to Highly Functionalized Trifluoromethyl-Substituted Triazines and Pyridines

ACS Catalysis, Journal Year: 2019, Volume and Issue: 9(5), P. 4600 - 4608

Published: April 12, 2019

Herein we disclose a silver-catalyzed [3 + 3] 1,3-dipolar cycloaddition reaction of trifluorodiazoethane with glycine imines. This exhibits manifold remarkable features, such as easily available substrates, high regio- and diastereoselectivities, mild conditions, good yields across broad spectrum substrates. Moreover, swift transformations the obtained tetrahydrotriazines provide efficient access to diverse set highly functionalized trifluoromethyl-substituted triazines pyridines. Particularly noteworthy is that trifluoromethylated 1,2,4-triazines demonstrate competent reactivity toward trans-cyclooctene (TCO) derivatives second-order rate constants (k2) up 99.24 M–1 s–1, which represents highest value involving date.

Language: Английский

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Synthesis of Benzofuran Derivatives through Cascade Radical Cyclization/Intermolecular Coupling of 2‐Azaallyls

Angewandte Chemie International Edition, Journal Year: 2019, Volume and Issue: 58(9), P. 2826 - 2830

Published: Jan. 9, 2019

Abstract Benzofurans are among the most popular structural units in bioactive natural products, however, synthesis of such structures by radical cyclization cascade reactions is rare. Herein, we report a mild and broadly applicable method for construction complex benzofurylethylamine derivatives through unique mechanism. Single‐electron transfer (SET) from 2‐azaallyl anions to 2‐iodo aryl allenyl ethers initiates that followed intermolecular radical–radical coupling. This expedient approach enables range polycyclic benzofurans would otherwise be difficult prepare.

Language: Английский

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