79201-73-3

Upstream product

• 775-12-2 diphenylsilane 
• 98-86-2 acetophenone 

Downstream Products

• 1445-91-6 (S)-1-phenylethanol 
• 1517-69-7 (R)-1-phenylethanol 

Relevant academic research and scientific papers

First study of rhodium(I) complexes with chiral sulfur-containing terpenoids as catalytic systems for ketone hydrosilylation

Using a “chiral pool” approach, a number of chiral thiolate and sulfide ligands based on natural terpenes and terpenoids have been synthesized in a few simple steps. Two new Rh-thiolate complexes with the formula [Rh(CO)2(μ-SR)]2 were obtained. The influence of these complexes and catalytic systems formed by combining the synthesized ligands with [Rh(CO)2(μ-Cl)]2 and [Rh(cod)(μ-Cl)]2, on the reaction rate, chemoselectivity, stereoselectivity and formation of tetraphenyldisiloxane in Rh-catalyzed asymmetric hydrosilylation of acetophenone as a model reaction have been studied. Mechanistic aspects of formation of silyl enol ether as a side product in the presence of S-containing ligands are presented.

Pseudo-enantiomeric carbohydrate-based N-heterocyclic carbenes as promising chiral ligands for enantiotopic discrimination

The practical synthesis of carbohydrate-based NHC-Rh complexes bearing C1 or C3 sterically differentiated positions, accessed by glycosylation or SNAr strategies, is reported. These catalysts exhibit pseudo-enantiomeric behaviour in the hydrosilylation of acetophenone. We show that steric bulk at C1 gives preference for (S)-phenyl-1-ethanol, while bulk at C3 leads to the (R)-enantiomer. These results represent the first example of pseudo-enantiomeric carbohydrate-based NHC ligands leading to enantiotopic discrimination.

Chiral Frustrated Lewis Pairs Catalyzed Highly Enantioselective Hydrosilylations of Ketones

A highly enantioselective Piers-type hydrosilylation of simple ketones was successfully realized using a chiral frustrated Lewis pair of tri-tert-butylphosphine and chiral diene-derived borane as catalyst. A wide range of optically active secondary alcohols were furnished in 80%—99% yields with 81%—97% ee's under mild reaction conditions.

Carbohydrate-based N-heterocyclic carbenes for enantioselective catalysis

Versatile syntheses of C2-linked and C2-symmetric carbohydrate-based imidazol(in)ium salts from functionalised amino-carbohydrate derivatives are reported. The novel NHCs were ligated to [Rh(COD)Cl]2 and evaluated in Rh-catalysed asymmetric hydrosilylation of ketones with good yields and promising enantioselectivities.

Synthesis, structure, and catalytic activity of a new chiral NHC-iridium(III) complex

The new chiral NHC-iridium complex 3 has been prepared in CH3CN from the reaction between [Ir(COD)Cl]2, NaOAc, KI, and dibenzimidazolium salt 2 which is derived from (S)-2,2′-diamino-6, 6′-dimethyl-1,1′-biphenyl. Complex 3 has been characterized by various spectroscopic techniques, elemental analyses, and X-ray diffraction analysis. It has a distorted-octahedral IrC2N2IH core structure, and shows good catalytic activity for the asymmetric hydrosilylation of arylmethyl ketones, leading to 1-arylethanol with moderate ee values.

Enantioselective zinc-catalyzed hydrosilylation of ketones using pybox or pybim ligands

The combination of ZnEt2 and chiral pyridinebisoxazoline (pybox) or pyridinebisimidazoline (pybim) ligands catalyzed the asymmetric hydrosilylation of aryl, alkyl, cyclic, heterocyclic, and aliphatic ketones. Under mild conditions, high yields and good enantioselectivities were achieved. ESI measurements allowed for the characterization of the active catalyst. Zincing outside of the pybox: A ZnEt2/pybox catalyst promotes the hydrosilylation of carbonyl compounds under mild conditions to afford high yields and good ee values for a broad range of aryl, alkyl, cyclic, heterocyclic, and aliphatic ketones.

Cobalt alkyl complexes of a new family of chiral 1,3-bis(2-pyridylimino) isoindolates and their application in asymmetric hydrosilylation

The synthesis of a new family of chiral tridentate monoanionic NNN-pincer ligands based on the 1,3-bis(2-pyridylimino)isoindoline (BPI) framework is reported. Ligands with substituents of varying steric demand were prepared starting from achiral and low priced materials. A kinetic enzymatic resolution was used as a key step for the preparation of enantiomerically pure ligands. In this way, both enantiomers of a given ligand could be produced enantioselectively (>99.5% ee). The corresponding cobalt alkyl complexes were obtained using a pyridine alkyl cobalt precursor complex and were applied in asymmetric hydrosilylation of several prochiral alkylaryl ketones with high yields (up to 100%) and enantioselectivity (up to 91% ee) to give the chiral alcohols after hydrolysis.

Design and synthesis of C2-symmetric N-heterocyclic carbene precursors and metal carbenoids

Chiral, C2-symmetric imidazolium and imidazolinium ions, as well as the corresponding copper- or silver-bound carbenoids, have been prepared. Structural study of these compounds by X-ray crystallography reveals a chiral pocket that surrounds th

Hydrosilylation of acetophenone with diphenylsilane in the presence of rhodium(I) complexes with chiral amines

New chiral rhodium complexes cis-[Rh(CO)2(RNH2)Cl] [RNH2 = (R)-(-)-cis-MyrtNH2, (R)-(-)-MenthylNH 2, (R)-(+)-BornylNH2] were synthesized and their catalytic properties in reactions of hydrosilylation of acetophenone with diphenylsilane were studied. It was shown that the reaction products were diphenyl-1- phenylethoxysilane, diphenyl-1-phenylvinyloxysilane and 1,1,3,3- tetraphenyldisiloxane. The best catalytic activity displayed (-)-cis-[Rh(CO)2(MenthNH2)Cl]. The hydrosilylation of acetophenone with diphenylsilane in the presence of [Rh(CO)2(μ-Cl) ]2 and [Rh(cod)Cl]2 and amines in situ was studied. The best ratio amine:complex = 5:1 was established. With the catalytic systems based on [Rh(cod)Cl]2 or [Rh(CO)2(μ-Cl)]2 the activity increased in the series of amines: (R)-(-)-cis-MyrtNH2 2 2, and (R)-(-)-MenthylNH2 2 2, respectively. The chemoselectivity maximum was observed in the presence of [Rh(cod)Cl]2 with (R)-(-)-MenthylNH 2 and [Rh (CO)2(μ-Cl)]2 with (R)-(+)-BornylNH2; maximum asymmetric induction was 43.5% ee at the use of [Rh(CO)2 (μ-Cl)]2 and (R)-(+)-BornylNH 2.

Enantioselective hydrosilylation of prochiral ketones catalyzed by chiral BINAP-copper(I) complexes

The CuCl/NaOt-Bu/BINAP system was found to efficiently catalyze the hydrosilylation of aryl alkyl ketones with excellent enantioselectivities by using phenyl methyl silane as a stoichiometric hydride source. High enantiomeric excesses (up to 97%) and excellent yields (up to 99%) were obtained.