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Asymmetric hydrosilylation of ketones catalyzed by complexes formed from trans-diaminocyclohexane-based diamines and diethylzinc.

Gajewy J, Gawronski J, Kwit M - Monatsh. Chem. (2012)

Bottom Line: Chiral acyclic and macrocyclic amines derived from trans-1,2-diaminocyclohexane in complexes with diethylzinc efficiently catalyze asymmetric hydrosilylation of aryl-alkyl and aryl-aryl ketones with enantiomeric excess of the product up to 86 %.A trianglamine ligand with a cyclic structure or the presence of an additional coordinating group increases the enantioselectivity of the reaction, in comparison with catalysis by a simple acyclic N,N'-dibenzyl-1,2-diaminocyclohexane ligand.In addition, the effect of the asymmetric activation of the catalyst by a variety of alcohols and diols is studied.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, A. Mickiewicz University, 60-780 Poznan, Poland.

ABSTRACT

Abstract: Chiral acyclic and macrocyclic amines derived from trans-1,2-diaminocyclohexane in complexes with diethylzinc efficiently catalyze asymmetric hydrosilylation of aryl-alkyl and aryl-aryl ketones with enantiomeric excess of the product up to 86 %. A trianglamine ligand with a cyclic structure or the presence of an additional coordinating group increases the enantioselectivity of the reaction, in comparison with catalysis by a simple acyclic N,N'-dibenzyl-1,2-diaminocyclohexane ligand. In addition, the effect of the asymmetric activation of the catalyst by a variety of alcohols and diols is studied.

No MeSH data available.


Related in: MedlinePlus

Effect of ligand structure on conversion and enantioselectivity of hydrosilylation of 4-methylacetophenone. Reaction conditions: 3.5 mol % catalyst, 1.2 equiv. silane, reaction time 24 h, toluene, RT; conversions and enantiomeric excesses were determined by HPLC with a Chiralpak IA column, average of two runs
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Fig3: Effect of ligand structure on conversion and enantioselectivity of hydrosilylation of 4-methylacetophenone. Reaction conditions: 3.5 mol % catalyst, 1.2 equiv. silane, reaction time 24 h, toluene, RT; conversions and enantiomeric excesses were determined by HPLC with a Chiralpak IA column, average of two runs

Mentions: We initially examined the effect of ligand structure on the yield and enantioselectivity of Zn-catalyzed hydrosilylation of 4-methylacetophenone (Fig. 3). The catalyst load in all cases was 3.5 mol %. Diphenylsilane was used as the reducing agent and all reactions were carried out in dry and degassed toluene for 24 h at room temperature.Fig. 3


Asymmetric hydrosilylation of ketones catalyzed by complexes formed from trans-diaminocyclohexane-based diamines and diethylzinc.

Gajewy J, Gawronski J, Kwit M - Monatsh. Chem. (2012)

Effect of ligand structure on conversion and enantioselectivity of hydrosilylation of 4-methylacetophenone. Reaction conditions: 3.5 mol % catalyst, 1.2 equiv. silane, reaction time 24 h, toluene, RT; conversions and enantiomeric excesses were determined by HPLC with a Chiralpak IA column, average of two runs
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4494764&req=5

Fig3: Effect of ligand structure on conversion and enantioselectivity of hydrosilylation of 4-methylacetophenone. Reaction conditions: 3.5 mol % catalyst, 1.2 equiv. silane, reaction time 24 h, toluene, RT; conversions and enantiomeric excesses were determined by HPLC with a Chiralpak IA column, average of two runs
Mentions: We initially examined the effect of ligand structure on the yield and enantioselectivity of Zn-catalyzed hydrosilylation of 4-methylacetophenone (Fig. 3). The catalyst load in all cases was 3.5 mol %. Diphenylsilane was used as the reducing agent and all reactions were carried out in dry and degassed toluene for 24 h at room temperature.Fig. 3

Bottom Line: Chiral acyclic and macrocyclic amines derived from trans-1,2-diaminocyclohexane in complexes with diethylzinc efficiently catalyze asymmetric hydrosilylation of aryl-alkyl and aryl-aryl ketones with enantiomeric excess of the product up to 86 %.A trianglamine ligand with a cyclic structure or the presence of an additional coordinating group increases the enantioselectivity of the reaction, in comparison with catalysis by a simple acyclic N,N'-dibenzyl-1,2-diaminocyclohexane ligand.In addition, the effect of the asymmetric activation of the catalyst by a variety of alcohols and diols is studied.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, A. Mickiewicz University, 60-780 Poznan, Poland.

ABSTRACT

Abstract: Chiral acyclic and macrocyclic amines derived from trans-1,2-diaminocyclohexane in complexes with diethylzinc efficiently catalyze asymmetric hydrosilylation of aryl-alkyl and aryl-aryl ketones with enantiomeric excess of the product up to 86 %. A trianglamine ligand with a cyclic structure or the presence of an additional coordinating group increases the enantioselectivity of the reaction, in comparison with catalysis by a simple acyclic N,N'-dibenzyl-1,2-diaminocyclohexane ligand. In addition, the effect of the asymmetric activation of the catalyst by a variety of alcohols and diols is studied.

No MeSH data available.


Related in: MedlinePlus