Isabelle Suisse

Chiral β-aminophosphine oxides as ligands for ruthenium assisted enantioselective transfer hydrogenation of ketones

Abstract Enantiopure β-aminophosphine oxide ligands have been synthesized and used in asymmetric transfer hydrogenation of ketones. Optically active alcohols are obtained in high yields and with up to 84% enantiomeric excess.

P-chiral β-aminophosphine oxides vs. β-aminophosphines as auxiliaries for ruthenium catalysed enantioselective transfer hydrogenation of arylketones

Abstract Enantiopure P-chiral β-aminophosphine oxides and the corresponding β-aminophosphines have been synthesised and used as chiral auxiliaries in ruthenium catalysed asymmetric transfer hydrogenation of arylketones producing optically active alcohols up to 80% ee. Both types of auxiliaries provide comparable induction levels but the β-aminophosphine oxide ligands induce higher catalytic activities generally. In some experiments, when changing the achiral arene ligand in the catalyst precursor, a peculiar reversal of the product configuration was observed.

A further application of TPPTS in catalysis: Efficient sucrose-butadiene telomerization using palladium catalysts in water

Sucrose-butadiene telomerization is efficiently carried out in water or water-organic medium in the presence of a palladium salt and TPPTS (TPPTS = trisodium tris(m-sulfonatophenyl)phosphine as catalyst. Mono- and dioctadienylether compounds are selectively obtained using a NaOH 1 M/isopropanol mixture.

Halide-free highly-pure imidazolium triflate ionic liquids: Preparation and use in palladium-catalysed allylic alkylation

The reaction of three oxygenated heterocycles (tetrahydrofuran, tetrahydropyran, 1,4-dioxane) with trifluoromethane sulfonic anhydride in the presence of the non-nucleophilic base poly(4-vinylpyridine) affords alkylditriflates quantitatively via ring opening. The alkylditriflates react with N-alkylimidazoles providing the bis-imidazolium bis-triflate salts in high yields. Hydroxymethyl substituted oxygenated heterocycles are converted into imidazolium triflate salts without opening of the heterocycle. Two imidazolium salts were characterized by X-ray crystallographic structure determination. The halide free ionic liquids were applied successfully as solvents in the palladium catalysed allylic alkylation. A co-crystal of 15 and tetrabutylammonium triflate has also been characterized by X-ray crystallographic structure analysis.

Chiral ligands derived from monoterpenes: application in the synthesis of optically pure secondary alcohols via asymmetric catalysis.

The preparation of optically pure secondary alcohols in the presence of catalysts based on chiral ligands derived from monoterpenes, such as pinenes, limonenes and carenes, is reviewed. A wide variety of these ligands has been synthesized and used in several catalytic reactions, including hydrogen transfer, C-C bond formation via addition of organozinc compounds to aldehydes, hydrosilylation, and oxazaborolidine reduction, leading to high activities and enantioselectivities.

Solvent free telomerization of butadiene with water into octadienols in the presence of nonionic surfactant : efficient micellar catalysis

Telomerization of butadiene with water into 2,7-octadien-1-ol using a palladiumhydrosoluble phosphine system was investigated. The reaction was carried out without solvent in the presence of carbon dioxide and a nonionic surfactant. Promoted effect of neutral surfactant appeared above the critical micelle concentration and the conversion and the selectivity depended on the structure of nonionic surfactant hydrophilic part. The role of the nonionic surfactant is discussed.

RHODIUM(I) BIS(AMINOPHOSPHANE) COMPLEXES AS CATALYSTS FOR ASYMMETRIC HYDROGENATION OF ACTIVATED KETONES

Abstract The synthesis of new homochiral bis(aminophosphanes) (BAMP) 1–5 and their application in rhodium based asymmetric hydrogenation of dihydro-4,4-dimethyl-2,3-furandione 12 and N -benzylbenzoylformamide 14 are presented. Under mild conditions, the hydrogenations led to high enantiomeric excesses (up to 87% and 75% ee respectively for both substrates).

Telomerisation of 1,3‐Butadiene with 1,4:3,6‐Dianhydrohexitols: An Atom‐Economic and Selective Synthesis of Amphiphilic Monoethers from Agro‐Based Diols

The telomerisation of 1,3-butadiene with a Pd/TPPTS catalytic system in water or an organic solvent was used for the synthesis of C8 ethers from isosorbide, an agro-based diol. The use of water/oil biphasic reaction conditions allowed the selective synthesis of monoethers with improved rates upon using inorganic bases as promotors. As isosorbide is a non-symmetric diol, the two hydroxyl groups display different reactivities. 2-O-substituted-monoethers were preferentially obtained if water was used as the solvent, whereas in DMSO 5-O-substituted monoethers were the major products. Complete conversions of isosorbide with up to 94% monoether selectivities were obtained. The optimized reaction conditions were successfully applied to isomannide and isoidide for the selective synthesis of the derived ethers. An improved reactivity of the endo-hydroxy groups of isosorbide and isomannide versus the exo-hydroxy groups of isosorbide and isoidide was observed if the reaction was performed in DMSO instead of water.

Synthesis of isosorbide: an overview of challenging reactions

Isosorbide is a diol derived from sorbitol and obtained through dehydration reactions that has raised much interest in the literature over the past few decades. Thus, this platform chemical is a biobased alternative to a number of petrosourced molecules that can find applications in a large number of technical specialty fields, such as plasticizers, monomers, solvents or pharmaceuticals. The synthesis of isosorbide is still a technical challenge, as several competitive reactions must be simultaneously handled to promote a high molar yield and avoid side reactions, like degradation and polymerization. In this purpose, many studies have proposed innovative and varied methods with promising results. This review gives an overview of the synthesis strategies and catalysts developed to access this very attractive molecule, pointing out both the results obtained and the remaining issues connected to isosorbide synthesis.

Nickel‐Catalysed Hydroalkoxylation Reaction of 1,3‐Butadiene: Ligand Controlled Selectivity for the Efficient and Atom‐Economical Synthesis of Alkylbutenyl Ethers

The nickel-catalysed hydroalkoxylation of butadiene is promoted by a nickel(0)/dppb catalyst (dppb = 1,4-bis(diphenylphosphino)butane; see scheme). By following this new synthetic procedure, alkylbutenyl ethers are readily obtained from an alcohol and 1,3-butadiene with exclusion of dimerisation and telomerisation products.