Oxiranes and Oxirenes: Monocyclic DOI

Michael D. Delost,

Jon Tryggvi Njardarson

Elsevier eBooks, Journal Year: 2019, Volume and Issue: unknown, P. 199 - 274

Published: Dec. 31, 2019

Language: Английский

Activating Pronucleophiles with High pKa Values: Chiral Organo‐Superbases DOI

Yu‐Hui Wang,

Zhong‐Yan Cao, Qinghua Li

et al.

Angewandte Chemie International Edition, Journal Year: 2019, Volume and Issue: 59(21), P. 8004 - 8014

Published: Dec. 2, 2019

Abstract Direct deprotonation represents an extremely simple, straightforward, and atom‐economic strategy to activate pronucleophiles bearing acidic proton. However, the difficulty often arises in activating with high p K a values by using conventional chiral tertiary amines. To overcome this challenge, handful of novel Brønsted superbases, including amidines, guanidines, cyclopropenimines, iminophosphoranes, have been discovered recent years. This minireview focuses on application these organo‐superbases catalytic asymmetric reactions weakly pronucleophiles, highlights their comparison amines, demonstrating highly efficient processes stereoselectivity controlled conversions superbases. The advantage new superbases brings great opportunity for developing more transformations pronucleophiles.

Language: Английский

Citations

59

Phosphorus‐Containing Superbases: Recent Progress in the Chemistry of Electron‐Abundant Phosphines and Phosphazenes DOI Creative Commons
Robin F. Weitkamp, Beate Neumann, Hans‐Georg Stammler

et al.

Chemistry - A European Journal, Journal Year: 2021, Volume and Issue: 27(42), P. 10807 - 10825

Published: May 25, 2021

The renaissance of Brønsted superbases is primarily based on their pronounced capacity for a large variety chemical transformations under mild reaction conditions. Four major set screws are available the selective tuning basicity: nature basic center (N, P, …), degree electron donation by substituents to central atom, possibility charge delocalization, and energy gain hydrogen bonding. Within past decades, plethora neutral electron-rich phosphine phosphazene bases have appeared in literature. Their outstanding properties advantages over inorganic or charged now made them indispensable as auxiliary deprotonation processes. Herein, an update chemistry phosphines phosphazenes given. In addition, due widespread interest, use catalysis ligands coordination highlighted.

Language: Английский

Citations

44

Recent Advances in Synthesis of Chiral Thioethers DOI
Hongyi Chen, Wenlong Jiang, Qingle Zeng

et al.

The Chemical Record, Journal Year: 2020, Volume and Issue: 20(11), P. 1269 - 1296

Published: Sept. 15, 2020

Abstract Chiral thioethers is an important class of organosulfur molecules with extensive applications, especially in the field medicine and organic synthesis. This review discusses recent progress synthesis enantioenriched chiral hopes to be helpful for related research future. It summarized from compounds‐participating reaction types, including nucleophilic substitution, cross coupling, sulfa‐Michael addition, sulfenylation, asymmetric allylic reaction, Doyle‐Kirmse Pummerer‐type rearrangement, Smiles [2,3] Stevens Sommelet‐Hauser rearrangement.

Language: Английский

Citations

47

Diversity‐Orientated Stereoselective Synthesis through Pd‐Catalyzed Switchable Decarboxylative C−N/C−S Bond Formation in Allylic Surrogates DOI
Lei Deng, Arjan W. Kleij, Weibo Yang

et al.

Chemistry - A European Journal, Journal Year: 2018, Volume and Issue: 24(72), P. 19156 - 19161

Published: Oct. 25, 2018

Switchable catalytic transformation of reactants can be a powerful approach towards diversity-orientated synthesis from easily available molecular synthons. Herein, an endogenous ligand-controlled, Pd-catalyzed allylic substitution allowing for either selective C-N or C-S bond formation using vinylethylene carbonates (VECs) and N-sulfonylhydrazones as coupling partners has been developed. This versatile methodology provides facile, divergent route the highly chemo- stereoselective functional sulfones sulfonohydrazides. The newly developed protocol features wide substrate scope (nearly 80 examples), broad group tolerance, potential late-stage functionalization bioactive compounds. isolation crystallographic analysis catalytically competent π-allyl Pd complex suggests that pathway leading to products proceeds through different manifold previously proposed VECs with nucleophiles.

Language: Английский

Citations

42

Organocatalytic Arylation of α‐Ketoesters Based on Umpolung Strategy: Phosphazene‐Catalyzed SNAr Reaction Utilizing [1,2]‐Phospha‐Brook Rearrangement DOI
Azusa Kondoh,

Takuma Aoki,

Masahiro Terada

et al.

Chemistry - A European Journal, Journal Year: 2018, Volume and Issue: 24(50), P. 13110 - 13113

Published: July 4, 2018

Abstract An organocatalytic arylation of α‐ketoesters was developed on the basis umpolung strategy. Phosphazene P2‐ t Bu efficiently catalyzes three‐component coupling reaction α‐ketoesters, a silylated secondary phosphite, and electron‐deficient fluoroarenes to provide α‐hydroxyester derivatives possessing an aryl group at α‐position. The involves catalytic generation α‐oxygenated ester enolates from through [1,2]‐phospha‐Brook rearrangement followed by S N Ar reaction.

Language: Английский

Citations

31

BIMP‐Catalyzed 1,3‐Prototropic Shift for the Highly Enantioselective Synthesis of Conjugated Cyclohexenones DOI Creative Commons
Jonathan C. Golec, Eve M. Carter, John W. Ward

et al.

Angewandte Chemie International Edition, Journal Year: 2020, Volume and Issue: 59(40), P. 17417 - 17422

Published: June 19, 2020

A bifunctional iminophosphorane (BIMP)-catalysed enantioselective synthesis of α,β-unsaturated cyclohexenones through a facially selective 1,3-prototropic shift β,γ-unsaturated prochiral isomers, under mild reaction conditions and in short times, on range structurally diverse substrates, is reported. α,β-Unsaturated cyclohexenone products primed for downstream derivatisation were obtained high yields (up to 99 %) consistently enantioselectivity % ee). Computational studies into the mechanism origins enantioselectivity, including multivariate linear regression TS energy, carried out data found be good agreement with experimental findings.

Language: Английский

Citations

27

Activating Pronucleophiles with High pKa Values: Chiral Organo‐Superbases DOI

Yu‐Hui Wang,

Zhong‐Yan Cao, Qinghua Li

et al.

Angewandte Chemie, Journal Year: 2019, Volume and Issue: 132(21), P. 8080 - 8090

Published: Dec. 2, 2019

Abstract Direct deprotonation represents an extremely simple, straightforward, and atom‐economic strategy to activate pronucleophiles bearing acidic proton. However, the difficulty often arises in activating with high p K a values by using conventional chiral tertiary amines. To overcome this challenge, handful of novel Brønsted superbases, including amidines, guanidines, cyclopropenimines, iminophosphoranes, have been discovered recent years. This minireview focuses on application these organo‐superbases catalytic asymmetric reactions weakly pronucleophiles, highlights their comparison amines, demonstrating highly efficient processes stereoselectivity controlled conversions superbases. The advantage new superbases brings great opportunity for developing more transformations pronucleophiles.

Language: Английский

Citations

20

Highly Stereoselective Palladium‐Catalyzed [3+2] Cycloaddition of Vinyl Epoxides and N‐Benzothiazolimines DOI
Xiaoxiao Song, Mengjie Gu, Xiaoyun Chen

et al.

Asian Journal of Organic Chemistry, Journal Year: 2019, Volume and Issue: 8(12), P. 2180 - 2183

Published: Nov. 2, 2019

Abstract An asymmetric [3+2] cycloaddition of racemic vinyl epoxides with N ‐benzothiazolimines has been presented under Pd‐catalysis. This transformation provides rapid access to highly functionalized oxazolidine scaffolds in generally good yields along high stereoselectivities (up 99% ee , 8.5 : 1 d.r.) mild conditions. The use chiral BINAP ligand enabled this a broad substrate tolerance.

Language: Английский

Citations

15

BIMP‐Catalyzed 1,3‐Prototropic Shift for the Highly Enantioselective Synthesis of Conjugated Cyclohexenones DOI
Jonathan C. Golec, Eve M. Carter, John W. Ward

et al.

Angewandte Chemie, Journal Year: 2020, Volume and Issue: 132(40), P. 17570 - 17575

Published: June 19, 2020

Abstract A bifunctional iminophosphorane (BIMP)‐catalysed enantioselective synthesis of α,β‐unsaturated cyclohexenones through a facially selective 1,3‐prototropic shift β,γ‐unsaturated prochiral isomers, under mild reaction conditions and in short times, on range structurally diverse substrates, is reported. α,β‐Unsaturated cyclohexenone products primed for downstream derivatisation were obtained high yields (up to 99 %) consistently enantioselectivity % ee ). Computational studies into the mechanism origins enantioselectivity, including multivariate linear regression TS energy, carried out data found be good agreement with experimental findings.

Language: Английский

Citations

5

Oxiranes and Oxirenes: Monocyclic DOI

Michael D. Delost,

Jon Tryggvi Njardarson

Elsevier eBooks, Journal Year: 2019, Volume and Issue: unknown, P. 199 - 274

Published: Dec. 31, 2019

Language: Английский

Citations

4