- Carbonyl and ester C-O bond hydrosilylation using κ4-diimine nickel catalysts
-
The synthesis of alkylphosphine-substituted α-diimine (DI) ligands and their subsequent addition to Ni(COD)2 allowed for the preparation of (iPr2PPrDI)Ni and (tBu2PPrDI)Ni. The solid state structures of both compounds were found to feature a distorted tetrahedral geometry that is largely consistent with the reported structure of the diphenylphosphine-substituted variant, (Ph2PPr DI)Ni. To explore and optimize the synthetic utility of this catalyst class, all three compounds were screened for benzaldehyde hydrosilylation activity at 1.0 mol% loading over 3 h at 25 °C. Notably, (Ph2PPr DI)Ni was found to be the most efficient catalyst while phenyl silane was the most effective reductant. A broad scope of aldehydes and ketones were then hydrosilylated, and the silyl ether products were hydrolyzed to afford alcohols in good yield. When attempts were made to explore ester reduction, inefficient dihydrosilylation was noted for ethyl acetate and no reaction was observed for several additional substrates. However, when an equimolar solution of allyl acetate and phenyl silane was added to 1.0 mol% (Ph2PPr DI)Ni, complete ester C-O bond hydrosilylation was observed within 30 min at 25 °C to generate propylene and PhSi(OAc)3. The scope of this reaction was expanded to include six additional allyl esters, and under neat conditions, turnover frequencies of up to 990 h-1 were achieved. This activity is believed to be the highest reported for transition metal-catalyzed ester C-O bond hydrosilylation. Proposed mechanisms for (Ph2PPr DI)Ni-mediated carbonyl and allyl ester C-O bond hydrosilylation are also discussed.
- Rock, Christopher L.,Groy, Thomas L.,Trovitch, Ryan J.
-
supporting information
p. 8807 - 8816
(2018/07/13)
-
- Method for Producing Acyloxysilanes, Acyloxysilanes Obtained Thereby, and Use of Same
-
An object of the invention is to provide a method for efficiently producing an acyloxysilane which is useful as a functional chemical, an acyloxysilane obtained thereby, and the use thereof. The present invention provides: a method for producing an acyloxysilane, including a reaction step of reacting an alkoxysilane with a carboxylic anhydride in the presence of a catalyst, wherein the alkoxysilane is a specified alkoxysilane represented by General Formula (I), the carboxylic anhydride is a specified carboxylic acid represented by General Formula (IIA) or (IIB), the catalyst is an acid catalyst, and an acyloxysilane obtained in the reaction step is a specified acyloxysilane represented by General Formula (IIIA) or (IIIB); and the use of the acyloxysilane as a surface treatment agent or the like.
- -
-
Paragraph 0131
(2018/03/25)
-
- Process for the continuous preparation of acyloxysilanes
-
Acyloxysilanes are prepared by a process of reacting an organochlorosilane with an excess of monocarboxylic anhydride at elevated temperature, thereby forming product acyloxysilane and by-product acyl chloride transferring the reaction mixture to the middle inlet of a separation tower having a still pot at its base, removing excess carboxylic anhydride by distillation at the tower top under reduced pressure, removing acyl chloride by-product from the separation tower, uniformly removing acyloxysilane from the tower still pot, and reacting virtually quantitatively the residual acid chloride present in the acyloxysilane removed from the still pot by adding a metal carboxylate to the acyloxysilane and separating the metal chlorides formed from the product.
- -
-
-