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• 557-20-0 diethylzinc 
• 1896-62-4 (E)-benzalacetone 
• 925-90-6 ethylmagnesium bromide 

Relevant academic research and scientific papers

Synthesis of new derivatives of copper complexes of Josiphos family ligands for applications in asymmetric catalysis

A series of new copper complexes containing chiral ferrocenyl diphosphine ligands of the Josiphos family have been prepared. These complexes have been studied in the catalytic asymmetric 1,2-addition of Grignard reagents to enones and aromatic ketones. Variation of the electronic and steric properties of the ligand resulted in a positive effect in the regio- and enantioselectivity of Grignard reagents to α-H-substituted enones using the ligand in which tert-butyl substituents were introduced in the diarylphosphine moiety. The copper complexes were also successfully applied in the catalytic asymmetric conjugate addition of Grignard reagents to enoates. No increase of enantioselectivity was observed in the catalytic asymmetric addition of linear Grignard reagents, compared to that of the commercially available ligand rev-Josiphos. The Royal Society of Chemistry 2014.

New ligands and structural insights into the catalytic asymmetric addition of organozinc reagents to ketones

The catalytic asymmetric addition of alkyl groups to ketones has received considerable attention. Outlined herein is the synthesis of two new ligands based on the C2-symmetric 11,12-diamino-9,10-dihydro-9,10- ethanoanthracene. The scope of the new ligands has been evaluated in the catalytic asymmetric addition of diethylzinc to a variety of ketones. Enantioselectivities as high as 99% have been achieved. The structures of two of these ligands have been determined by X-ray crystallography and are compared with related structures. Additionally, the structure of a titanium complex bound to a bis(sulfonamide) diol ligand is reported.

Catalytic asymmetric addition of alkylzinc and functionalized alkylzinc reagents to ketones

(Chemical Equation Presented) We describe our full report of the catalytic asymmetric addition of simple and functionalized dialkylzinc reagents to a broad range of saturated ketones and enones. The functionalized organozinc reagents contain esters, silyl

A green chemistry approach to a more efficient asymmetric catalyst: Solvent-free and highly concentrated alkyl additions to ketones

There is a great demand for development of catalyst systems that are not only efficient and highly enantioselective but are also environmentally benign. Herein we report investigations into the catalytic asymmetric addition of alkyl and functionalized alk

trans-1,2-diaminocyclopentane-based catalyst for the asymmetric addition of alkyl-, aryl-, and vinyl groups to ketones

The catalytic asymmetric addition of ethyl-, phenyl-, and 1-hexenyl groups to ketones is reported. The new catalyst, generated from titanium wopropoxide and a bis(sulfonamide) diol ligand based on frans-1,2-diaminocyclopentane, gives good to excellent ena

Synthesis of new C2-symmetrical bis(hydroxycamphorsulfonamide) ligands and their application in the enantioselective addition of dialkylzinc reagents to aldehydes and ketones

The preparation of several C2-symmetric disulfonamides derived from chiral camphorsulfonyl chloride and different diamines (with or without stereogenic elements) is described. Their use in the titanium tetraisopropoxide-promoted enantioselective addition of dialkylzinc reagents to aldehydes has been tested, the best enantiomeric excess being up to 76%. Moreover, the unusual addition of dialkylzinc reagents to ketones can also be achieved with excellent enantioselectivity (up to 92% e.e.) using this type of ligand. When using para-substituted phenones as electrophiles, the enantiomeric excess of the resulting tert-alcohol is independent of the electronic properties of the group attached to the aromatic ring of the phenone. In the case of using more hindered ketones the enantioselectivity is lower, so indicating a steric influence in the reaction.

CATALYSTS, METHODS FOR MAKING SAID CATALYSTS, AND METHODS FOR MAKING CHIRAL COMPOUNDS WITH HIGH ENANTIOSELECTIVITY

The present invention relates to compounds useful as catalysts in asymmetric synthesis of chiral compounds, methods for the synthesis of said catalysts, and methods for synthesizing chiral compounds with high enantioselectivity.

A practical catalytic asymmetric addition of alkyl groups to ketones

Many catalysts will promote the asymmetric addition of alkylzinc reagents to aldehydes. In contrast, there are no reports of additions to ketones that are both general and highly enantioselective. We describe herein a practical catalytic asymmetric additi

Highly enantioselective addition of dialkylzinc reagents to ketones promoted by titanium tetraisopropoxide

The preparation of several 1,2-bis(hydroxycamphorsulfonamido)cyclohexenes from the corresponding 1,2-cyclohexenediamine and camphorsulfonyl chloride is described. The use of these ligands to promote the enantioselective addition of dialkylzinc to ketones

Highly enantioselective addition of primary alkyl Grignard reagents to carbocyclic and heterocyclic arylketones in the presence of magnesium TADDOLate preparative and mechanistic aspects

In the presence of equimolar amounts of the Mg alkoxide from α,α,α',α'-tetraphenyl-2,2-dimethyl-1,3-dioxolan-4,5-dimethanol (a TADDOL) primary Grignard reagents (Et, Pr, Bu, Oct, 3-butenyl) add to carbo- and heteroaromatic methyl ketones in THF at -100°C to give tertiary alcohols of enantiomeric excesses reaching values above 98%. The scope and limitation of the method are investigated. The reaction, which occurs in a vigorously stirred heterogeneous mixture, give best results in the absence of steric hindrance of the reacting centers; Grignard reagents made from alkyl bromides are superior to those obtained from chlorides; there is a perfect linear relationship between the ee of the TADDOL and of the product 2-phenyl-2-decanol; those tertiary alcohols of which the absolute configuration is known, are formed by nucleophilic attack from the Re face of the keto carbonyl groups. Three tentative mechanistic models for the stereochemical course of the reaction are discussed.