Publications de Jonathan Brand

Gold-catalyzed direct alkynylation of tryptophan in peptides using TIPS-EBX

Jérôme Waser, Jonathan Brand, Gergely Laszlo Tolnai

The selective functionalization of peptides containing only natural amino acids is important for the modification of biomolecules. In particular, the installation of an alkyne as a useful handle for bioconjugation is highly attractive, but the use of a car ...

2016

Gold-Catalyzed Regioselective Synthesis of 2- and 3-Alkynyl Furans

Jérôme Waser, Jonathan Brand, Yifan Li

Wiley-VCH Verlag GmbH2013

C2-Selective Direct Alkynylation of Indoles

Stephanie Ganss, Jérôme Waser, Jonathan Brand, Gergely Laszlo Tolnai

The first C2-selective alkynylation of indoles using the hypervalent iodine reagent triisopropylsilylethyny1-1,2-benziodoxol-3(1H)-one (TIPS-EBX) with Pd(II) as a catalyst is described. This convenient and robust method gives a single-step access to substi ...

American Chemical Society2013

Gold-Catalyzed Alkynylation: Acetylene-Transfer instead of Functionalization

Jérôme Waser, Jonathan Brand, Yifan Li

Over the last fifteen years, gold has been raised from the status of an inert noble metal to one of the most-often-used catalysts in synthetic chemistry. The functionalization of the triple bond of alkynes has been especially successful in this respect. In ...

Wiley-V C H Verlag Gmbh2013

Ethynylbenziodoxolones (EBX) as Reagents for the Ethynylation of Stabilized Enolates

Davinia Fernández González, Jérôme Waser, Jonathan Brand

Herein, we report a detailed study on the electrophilic alkynylation of cyclic keto esters and amides with ethynylbenziodoxolone (EBX) reagents. The structure and stability of this class of reagents is first described more in details. Differential scanning ...

Wiley-Blackwell2013

Para-Selective Gold-Catalyzed Direct Alkynylation of Anilines

Jérôme Waser, Jonathan Brand

A method for the para-selective alkynylation of anilines is reported using AuCl as catalyst and triisopropylsilylethynyl-1,2-benziodoxol-3(1H)-one (TIPS-EBX) as an electrophilic acetylene equivalent. Para-alkynyl anilines substituted at positions 2 or 3 we ...

American Chemical Society2012

Electrophilic alkynylation: the dark side of acetylene chemistry

Jérôme Waser, Jonathan Brand

In addition to the well-established nucleophilic alkynylation, the use of electrophilic alkynes can expand tremendously the scope of acetylene transfer reactions. The use of metal catalysis has recently led to a rebirth of this research area. Halogenoalkyn ...

Royal Society of Chemistry2012

Ethynyl Benziodoxolones for the Direct Alkynylation of Heterocycles: Structural Requirement, Improved Procedure for Pyrroles, and Insights into the Mechanism

Rosario Scopelliti, Jérôme Waser, Jonathan Brand

This report describes a full study of the gold-catalyzed direct alkynylation of indoles, pyrroles, and thiophenes using alkynyl hypervalent iodine reagents, especially the study of the structural requirements of alkynyl benziodoxolones for an efficient ace ...

2012

Development of Catalytic Umpolung : Part 1: Direct Alkynylation of Heterocycles and Electron-Rich Aromatics using Alkynyl-Benziodoxolones - Part 2: Synthesis of New Bifunctional (Thio)urea-Carbene Catalysts

Jonathan Brand

The development of efficient synthetic methodologies is crucial to access complex molecules in an economic, eco-friendly and safe way. The reversal of the intrinsic reactivity of functional groups, called Umpolung, allows alternative synthetic strategies a ...

EPFL2012

Synthesis of 1-[(Triisopropylsilyl)ethynyl]-1 lambda(3),2-benziodoxol-3(1H)-one and Alkynylation of Indoles, Thiophenes, and Anilines

Jérôme Waser, Jonathan Brand

An efficient procedure was developed for the synthesis of 1-[(triisopropylsilyl)ethynyl]-1 lambda(3),2-benziodoxol-3(1H)-one on a 100-mmol (36-g) scale. The benziodoxolone can be used for the gold-catalyzed direct alkynylation of indole, 2-hexylthiophene, ...

2012

Cyclopropanes and Hypervalent Iodine Reagents: High Energy Compounds for Applications in Synthesis and Catalysis

Davinia Fernández González, Jérôme Waser, Filippo De Simone, Jonathan Brand, Stefano Nicolai

One of the major challenges faced by organic chemistry is the efficient synthesis of increasingly complex molecules. Since October 2007, the Laboratory of Catalysis and Organic Synthesis (LCSO) at EPFL has been working on the development of catalytic react ...

2011

Benziodoxole-based hypervalent iodine reagents for atom-transfer reactions

Davinia Fernández González, Jérôme Waser, Jonathan Brand, Stefano Nicolai

In the last decades, hypervalent iodine reagents have raised from chemical curiosities to mainstream reagents in organic synthesis. The use of benziodoxole-derived reagents has been especially successful in oxidation methods, whereas non-cyclic iodinanes h ...

Royal Society of Chemistry2011

One-pot gold-catalyzed synthesis of 3-silylethynyl indoles from unprotected o-alkynylanilines

Jérôme Waser, Jonathan Brand

The Au(III)-catalyzed cyclization of 2-alkynylanilines was combined in a one-pot procedure with the Au(I)-catalyzed C3-selective direct alkynylation of indoles using the benziodoxolone reagent TIPS-EBX to give a mild, easy and straightforward entry to 2-su ...

2011

Benziodoxole-based hypervalent iodine reagents for atom-transfer reactions

Davinia Fernández González, Jérôme Waser, Jonathan Brand, Stefano Nicolai

In the last decades, hypervalent iodine reagents have raised from chemical curiosities to mainstream reagents in organic synthesis. The use of benziodoxole-derived reagents has been especially successful in oxidation methods, whereas non-cyclic iodinanes h ...

Royal Society of Chemistry2011

Ethynyl-1,2-benziodoxol-3(1 H)-one (EBX): An Exceptional Reagent for the Ethynylation of Keto, Cyano, and Nitro Esters

Davinia Fernández González, Jérôme Waser, Jonathan Brand

Hot alkyne! The in situ generation of Ethynyl-1,2-BenziodoXol-3(1H)-one (EBX) from the corresponding silyl protected reagent using TBAF is reported. EBX displayed exceptional acetylene transfer ability to stabilized enolates, even at –78 °C. The mild react ...

2010

Synthesis of Chiral Bifunctional (Thio)Urea N-Heterocyclic Carbenes

Jérôme Waser, Jonathan Brand, Jose Ignacio Osuna Siles

The rapid and modular synthesis of the first bifunctional N-heterocyclic carbenes bearing a (thio)urea moiety as H-bond donor group was reported. Different analogues could be accessed in seven steps from cheap (S)-pyroglutamic acid in good overall yields ( ...

Georg Thieme Verlag2010

Direct Alkynylation of Thiophenes: Cooperative Activation of TIPS–EBX with Gold and Brønsted Acids

Jérôme Waser, Jonathan Brand

United we stand! Cooperative activation of the hypervalent-iodine reagent TIPS-EBX with a gold catalyst and a Brønsted acid allowed the first direct ethynylation of thiophenes at room temperature (see scheme; TFA=trifluoroacetic acid). The obtained ethynyl ...

Wiley-VCH Verlag GmbH2010

Direct Alkynylation of Indole and Pyrrole Heterocycles

Julie Charpentier, Jérôme Waser, Jonathan Brand

Easy does it: The unique properties of benziodoxolone alkynyl periodinane 1 and gold catalysts have allowed the development of a high yielding, operationally simple (room temperature, no dry solvents or inert conditions, commercially available catalyst) re ...

Wiley-VCH Verlag GmbH2009