Jerome Waser
École Polytechnique Fédérale de Lausanne
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Featured researches published by Jerome Waser.
Chemical Society Reviews | 2012
Jonathan P. Brand; Jerome Waser
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. Halogenoalkynes, hypervalent alkynyliodoniums, acetylene sulfones and in situ oxidized terminal acetylenes are the most often used reagents for electrophilic alkynylation. Heteroatoms such as N, O, S and P can be now efficiently alkynylated. For C-C bond formation, electrophilic acetylenes can be coupled with different organometallic reagents. Recently, the first breakthrough in direct C-H and C[double bond, length as m-dash]C bond alkynylation has also been reported. Finally, sulfonyl acetylenes are efficient for alkyne transfer on carbon-centered radicals.
Angewandte Chemie | 2010
Jonathan P. Brand; Jerome Waser
United we stand! Cooperative activation of the hypervalent-iodine reagent TIPS-EBX with a gold catalyst and a Bronsted acid allowed the first direct ethynylation of thiophenes at room temperature (see scheme; TFA=trifluoroacetic acid). The obtained ethynylthiophenes are important building blocks for organic dyes and electronic materials.
Angewandte Chemie | 2013
Yifan Li; Jonathan P. Brand; Jerome Waser
Keywords: C-H functionalization ; domino reactions ; furans ; gold ; hypervalent iodine Reference EPFL-REVIEW-189600doi:10.1002/anie.201302210View record in Web of Science Record created on 2013-10-01, modified on 2017-08-01
Angewandte Chemie | 2011
Stefano Nicolai; Cyril Piemontesi; Jerome Waser
Sweet cyclizations: The synthesis of pyrrolizidines and indolizidines has been achieved. Olefins were subjected to an intramolecular palladium-catalyzed aminoalkynylation with the hypervalent iodine reagent TIPS-EBX. After removal of the protecting group, a two-step cyclization sequence and subsequent reduction led to the natural product (±)-trachelanthamidine (see scheme; TIPS-EBX=triisopropylsilyl ethynylbenziodoxolone).
Chemistry: A European Journal | 2010
Davinia Fernández González; Jonathan P. Brand; Jerome Waser
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 reaction conditions allowed the first ethynylation reactions of linear keto, cyano and nitro esters in high yields to give all-carbon quaternary centers or non-natural amino acids after selective reduction of the nitro group.
Chemistry: A European Journal | 2012
Jonathan P. Brand; Clara Chevalley; Rosario Scopelliti; Jerome Waser
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 acetylene transfer to heterocycles. An improved procedure for the alkynylation of pyrroles using pyridine as additive is also reported. Nineteen alkynyl benziodoxol(on)es were synthesized and evaluated in the direct alkynylation of indoles and/or thiophenes. Bulky silyl groups as acetylene substituents were optimal. Nevertheless, transfer of aromatic acetylenes to thiophene was achieved for the first time. An accelerating effect of a methyl substituent in both the 3- and 6-position of triisopropylsilylethynyl-1,2-benziodoxol-3(1H)-one (TIPS-EBX) on the reaction rate was observed. Competitive experiments between substrates of different nucleophilicity, deuterium labeling experiments, as well as the regioselectivity observed are all in agreement with electrophilic aromatic substitution. Gold(III) 2-pyridinecarboxylate dichloride was also an efficient catalyst for the reaction. Investigations indicated that gold(III) could be eventually reduced to gold(I) during the process. As a result of these investigations, a π activation or an oxidative mechanism are most probable for the alkynylation reaction.
Angewandte Chemie | 2010
Filippo De Simone; Juerg Gertsch; Jerome Waser
Mild Control: Selective cyclization of aminocyclopropanes on the N1 or C3 positions of indole was achieved by tuning the catalyst and solvent. The new strategy was applied to the formal synthesis of aspidospermidine and the total synthesis of goniomitine in 13 steps and 11% overall yield. The first studies on the bioactivity of goniomitine demonstrated significant cytotoxicity against several tumor cell lines (IC50: 150-400 nM).
Organic Letters | 2013
Gergely L. Tolnai; Stephanie Ganss; Jonathan P. Brand; Jerome Waser
The first C2-selective alkynylation of indoles using the hypervalent iodine reagent triisopropylsilylethynyl-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 substituted alkynyl indoles with very high C2 selectivity. The reaction is orthogonal to classical Pd(0) cross-coupling reactions, as it is tolerant to bromide and iodide substituents. The used silyl protecting group can be easily removed to give terminal acetylenes.
Angewandte Chemie | 2011
Florian de Nanteuil; Jerome Waser
With nitrogen too: The first catalytic [3+2] annulation of aminocyclopropanes with enol ethers is reported (see scheme; Phth=phthaloyl). The reaction worked with easily accessible phthalimidocyclopropanes using 5 mol % of SnCl4 in nearly quantitative yields. Polysubstituted cyclopentylamines, which are often present in bioactive compounds, were obtained with high diastereoselectivity and enantiospecificity.
Angewandte Chemie | 2016
Yifan Li; Durga Prasad Hari; Maria Victoria Vita; Jerome Waser
Hypervalent iodine compounds are privileged reagents in organic synthesis because of their exceptional reactivity. Among these compounds, cyclic derivatives stand apart because of their enhanced stability. They have been widely used as oxidants, but their potential for functional-group transfer has only begun to be investigated recently. The use of benziodoxol(on)es for trifluoromethylation (Tognis reagents) is already widely recognized, but other transformations have also attracted strong interest recently. In this Review, the development in the area since 2011 will be presented. After a short summary of synthetic methods to prepare benziodoxol(on)e reagents, their use to construct carbon-heteroatom and carbon-carbon bonds will be presented. In particular, the introduction of alkynes by using ethynylbenziodoxol(on)e (EBX) reagents has been highly successful. Breakthroughs in the introduction of alkoxy, azido, difluoromethyl, and cyano groups will also be described.