Publications related to Atropisomer

Recent advances in Rh(I)-catalyzed enantioselective C-H functionalization

Nicolai Cramer, Yi Zhang, Shouguo Wang, Zhen Chen

Chiral carbon-carbon (C-C) and carbon-heteroatom (C-X) bonds are pervasive and very essential in natural products, bioactive molecules, and functional materials, and their catalytic construction has emerged as one of the hottest research fields in syntheti ...

Royal Society of Chemistry2024

Architecture-Controllable Single-Crystal Helical Self-assembly of Small-Molecule Disulfides with Dynamic Chirality

Lukas Pfeifer, Qixing Zhang

Beyond the common supramolecular helical polymers in solutions, controlling single-crystal helical self-assembly with precisely defined chirality and architectures has been challenging. Here, we report that simply merging static homochiral amino acids with ...

AMER CHEMICAL SOC2023

A five-stranded heterometallic helicate

Kay Severin, Farzaneh Fadaei Tirani, Sylvain Alexandre Marie Sudan

A penta-stranded helicate was obtained by combining Pd(CH3CN)42 with La(NO3)3 and a polydentate ligand. The helicate displays low symmetry, both in solution and in the solid state. A dynamic interconversion between the penta-stranded helicate and a ...

Royal Society of Chemistry2023

Atropo‐Enantioselective Oxidation‐Enabled Iridium(III)‐Catalyzed C−H Arylations with Aryl Boronic Esters

Nicolai Cramer

Atropo-enantioselective biaryl coupling through C−H bond functionalization is an emerging technology allowing direct construction of axially chiral molecules. This approach is largely limited to electrophilic coupling partners. We report a highly atropo-en ...

Wiley-VCH Verlag GmbH2021

Intermolecular Pd(0)-Catalyzed Atropo-enantioselective C-H Arylation of Heteroarenes and Other Investigations into the Enantioselective Activation of Challenging C(sp3)-H Bonds

Qui-Hien Nguyen

The direct construction of stereogenic axes by enantioselective C-H arylation has been regarded as a very challenging transformation. Very few examples have been reported, despite the indisputable straight-forwardness of the methodology. This is due to the ...

EPFL2021

Palladium-Catalyzed Enantioselective Cacchi Reaction: Asymmetric Synthesis of Axially Chiral 2,3-Disubstituted Indoles

Qian Wang, Jieping Zhu, Hua Wu, Yuping He

We report herein the first examples of a palladiumcatalyzed enantioselective Cacchi reaction for the synthesis of indoles bearing a chiral C2-aryl axis. In the presence of a catalytic amount of Pd(OAc)2 and (R,R)-QuinoxP* ligand, reaction of N-aryl(alkyl)s ...

Wiley-VCH Verlag GmbH2020

Intermolecular Palladium(0)-Catalyzed Atropo-enantioselective C-H Arylation of Heteroarenes

Nicolai Cramer, Qui-Hien Nguyen

Atropisomeric (hetero)biaryls are motifs with increasing significance in ligands, natural products, and biologically active molecules. The straightforward construction of the stereogenic axis by efficient C-H functionalization methods is extremely rare and ...

2020

Development of Catalytic Asymmetric C-H Functionalizations with Chiral Cyclopentadienyl Iridium(III) Complexes

Yun-Suk Jang

Cp*Ir(III) catalyzed C-H functionalization is a growing field, since it provides novel complementary reactivities, but enantioselective C-H functionalization reactions with this metal remain a niche. This thesis investigates CpXIr(III) catalyzed asymmetric ...

EPFL2019

Rhodium(III)-Catalyzed Enantiotopic C-HActivation Enables Access to P-Chiral Cyclic Phosphinamides

Nicolai Cramer, Yang Sun

Compounds with stereogenic phosphorus atoms are frequently used as ligands for transition-metal as well as organocatalysts. A direct catalytic enantioselective method for the synthesis of P-chiral compounds from easily accessible diaryl phosphinamides is p ...

Wiley-Blackwell2017

Vibrational Signatures of Conformer-Specific Intramolecular Interactions in Protonated Tryptophan

Natalia Nagornova, Oleg Boyarkine, Aleksandr Pereverzev

Because of both experimental and computational challenges, protonated tryptophan has remained the last aromatic amino acid for which the intrinsic structures of low-energy conformers have not been unambiguously solved. The IR-IR UV hole-burning spectroscop ...

Amer Chemical Soc2016

Rotational barriers of biphenyls having heavy heteroatoms as ortho-substituents: experimental and theoretical determination of steric effects

The free energies of activation for the aryl-aryl rotation of 17 biphenyl derivatives, bearing a heavy heteroatom (S, Se, Te, P, Si, Sn) as ortho substituent, have been measured by variable temperature NMR. These numbers, so called B values, represent a me ...

2012

The biphenyl-monitored effective size of unsaturated functional or fluorinated ortho substituents

The size of a series of typical substituents has been probed by dynamic NMR measurements of the barriers to aryl-aryl rotation of the corresponding biphenyls. The resulting B values are meaningful because only mono-ortho substituted compounds were investig ...

2010

Reactivity Of Arylnitrile Oxides And C-Aroyl-N-Phenylnitrones With 3-Methylenedihydro-(3H)-Furan-2-One And Itaconic Anhydride

Christophe Roussel

1,3-dipolar cycloaddition is a powerful route for the synthesis of five-membered heterocycles. The [3+2] cycloadditions of some alpha-methylene-gamma-buryrolactones, namely 3-methylenedihydro-(3H)-furan-2-one (1) and itaconic anhydride (2) were Studied. Th ...

2009

B Values as a Sensitive Measure of Steric Effects

Torsional barriers of 15 ortho-substituted biphenyls have been determined computationally using the B3LYP density functional and experimentally by variable-temperature ("dynamic") nuclear magnetic resonance. Taking advantage of the 3'-isopropyldimethylsily ...

2009

Chiral recognition and supramolecular self-assembly of adsorbed amino acids and dipeptides at the submolecular level

Magalí Alejandra Lingenfelder

This thesis deals with the supramolecular organization of chiral aminoacids and dipeptides on metal surfaces. The emergence of homochirality in biomolecular systems is one of the most intriguing open questions of Nature. The self-assembly and amplification ...

EPFL2008

Spectroscopic signatures of gas-phase helices: Ac-Phe-(Ala)5-Lys-H+ and Ac-Phe-(Ala)10-Lys-H+

Thomas Rizzo, Oleg Boyarkine

We apply gas-phase double resonance spectroscopic techniques to two helical peptides, Ac-Phe-(Ala)5-Lys-H+ and Ac-Phe- (Ala)10-Lys-H+, using electrospray ionization combined with photofragmentation in a cold, 22-pole ion trap. Despite the large size of the ...

2007

Embedding an Allylmetal Dimer in a Chiral Cavity: The Unprecedented Stereoselectivity of a Twofold Wittig [1,2]-Rearrangement

Frédéric Bailly

After alpha,alpha'-dimetalation, both 2,2'-diallyloxy-1,1'-binaphthyl and 2,2'-di-2-methylallyloxy-1,1'-binaphthyl undergo the Wittig rearrangement with perfect diastereoselectivity. When racemic 1,1'-binaphthyl-2,2'-diol ("BINOL") is used as the starting ...

2006