Article
Chemistry, Inorganic & Nuclear
Jose Antonio Fernandez, Juan Manuel Garcia, Pablo Rios, Amor Rodriguez
Summary: The efficient catalytic hydrosilylation of ketones and aldehydes using a nickel pincer hydride complex supported by a diphosphino-boryl ligand has been studied. The presence of a boron group within the ligand skeleton enhances the catalytic activities for ketones compared to other related pincer systems. The reaction mechanism involves the initial formation of an alkoxide complex, followed by reaction with the silane to release the corresponding silyl ether and regenerate the catalyst, as supported by experimental and theoretical analysis.
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
(2021)
Article
Chemistry, Organic
Shuangshuang Ji, Jianfeng Sheng, Shang Gao, Zhipeng Pei, Fuming Ying, Jinshuai Song, Yanyan Zhu
Summary: The use of imine compounds to generate alkyl radicals has been explored by synthetic chemists, although the mechanism of this conversion is not yet fully understood. A recent study used density functional theory calculations to investigate the mechanisms of photocatalyzed imidoyl radical formation and conversion. The study found that a sequential energy transfer, single electron transfer, and proton transfer pathway was favorable for imidoyl radical generation. Interestingly, a substrate lacking 2,4,6-trimethoxy substituents exhibited poor reactivity due to its weak reduction ability and acidity in both the ground state and photo-excited state.
ORGANIC CHEMISTRY FRONTIERS
(2023)
Article
Chemistry, Organic
Piers St. Onge, Shajia I. Khan, Adam Cook, Stephen G. Newman
Summary: A reductive detrifluoromethylation protocol using an alkoxide base and silicon hydride species has been developed. Various pyridine and quinoline substrates with alkyl, aryl, and amino functional groups are reduced with moderate to high yields. The reaction selectively reduces C(sp2)-CF3 groups at the 2-position on the pyridine ring, while leaving trifluoromethyl groups intact elsewhere on the molecule. Preliminary mechanistic studies indicate that the combination of silane and base generates a strongly reducing system that can transfer electrons to electron-deficient pi systems.
Article
Chemistry, Multidisciplinary
Nils Ansmann, Deborah Hartmann, Sonja Sailer, Philipp Erdmann, Rezisha Maskey, Marcel Schorpp, Lutz Greb
Summary: In this study, hypercoordinated silicon anions were characterized using a new donor-free polymeric form of Lewis superacidic bis(perchlorocatecholato)silane 1. The results provide insights into the role of silicon hypercoordination in synthesis and catalysis, and suggest pronounced substrate activation.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Physical
Joshua A. Clarke, Georgii Nikonov
Summary: A highly selective catalytic reduction of tertiary amides to aldehydes has been reported. The catalytic system KOtBu/(EtO)(2)MeSiH showed high activity in converting tertiary amides to silylated hemiaminals, which can be further converted to aldehydes under mild conditions. The reaction is compatible with various functional groups, but poorly tolerated easily reducible functional groups such as esters, ketones, and aldehydes. This transition metal-free strategy provides a cheap and readily available method for the efficient reduction of tertiary amides to aldehydes.
Article
Chemistry, Organic
Kazuto Takaishi, Ritsuki Nishimura, Yuha Toda, Hajime Morishita, Tadashi Ema
Summary: Catalytic CO2 reduction with phenylsilane under solvent-free conditions was utilized to synthesize 3,4-dihydropyrans from beta dicarbonyl compounds and styrenes in a one-pot reaction. The synthesis involves three steps: (1) formation of bis(silyl)acetal from CO2 and phenylsilane, followed by a domino reaction of (2) Knoevenagel condensation and (3) inverse-electron-demand oxa-Diels-Alder reaction. The first step is catalyzed by a pentanuclear ZnII complex (0.07 mol %) to generate bis(silyl)acetals, which are then hydrolyzed into formaldehyde for the second step.
Review
Polymer Science
Ilya Krizhanovskiy, Maxim Temnikov, Yuriy Kononevich, Anton Anisimov, Fedor Drozdov, Aziz Muzafarov
Summary: This article presents the main developments in utilizing the thiol-ene reaction in silicone chemistry, covering the transformation from monomers to materials. The advantages and disadvantages of this reaction are illustrated with different examples, and a critical analysis is conducted comparing it to the hydrosilylation reaction.
Article
Chemistry, Multidisciplinary
Sinem Guven, Gourab Kundu, Andrea Wessels, Jas S. Ward, Kari Rissanen, Franziska Schoenebeck
Summary: In this study, a remote functionalization strategy was reported for the Z-selective synthesis of silyl enol ethers of (hetero)aromatic and aliphatic ketones via Ni-catalyzed chain walking. The positional selectivity is controlled by the directionality of the chain walk, independent of the resulting silyl enol ether's thermodynamic preferences. Mechanistic data indicate the formation of a Ni-(I) dimer under these conditions, which serves as a catalyst resting state and converts to an active chain-walking/functionalization catalyst, ultimately generating a stabilized eta(3)-bound Ni-(II) enolate as the key selectivity-controlling intermediate.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Organic
Hongbin Zhai, Zhenhua Wang, Kewei Chen, Tian-Yu Sun, Jian Wei, Yun-Dong Wu
Summary: The first asymmetric total synthesis of indole alkaloid arbophyllidine has been achieved, featuring key reactions such as intramolecular reductive Heck reaction, Fischer indolization, and oxidative lactonization. Density functional theory calculations were employed to provide a comprehensive understanding of the oxidative lactonization.
ORGANIC CHEMISTRY FRONTIERS
(2022)
Article
Chemistry, Physical
Igor Fokin, Kai-Thorben Kuessner, Inke Siewert
Summary: This article introduces a method that combines organometallic catalysis and electrochemistry for the electrohydrogenation of ketones and aldehydes. Mechanistic analysis shows that by using a manganese catalyst and a proton relay, electrohydrogenation of C=O bonds can be achieved with high selectivity. The method demonstrates catalytic efficiency and high conversion rate under mild conditions.
Article
Chemistry, Multidisciplinary
Aolin Cheng, Liangliang Zhang, Qinghai Zhou, Tao Liu, Jing Cao, Guoqing Zhao, Kun Zhang, Guanshui Song, Baoguo Zhao
Summary: The direct asymmetric aldol reaction of glycinates has been achieved by using chiral N-methyl pyridoxal as the catalyst, leading to high yields of chiral beta-trifluoromethyl-beta-hydroxy-alpha-amino-acid esters with excellent stereoselectivity and enantioselectivity.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Applied
Nikita V. V. Shvydkiy, Klimentiy V. V. Rimskiy, Dmitry S. S. Perekalin
Summary: The readily available cyclobutadiene platinum complex [(C4Et4)PtCl2] can catalyze the hydrosilylation of alkenes and alkynes. The reaction occurs at room temperature and does not require any solvent. The products obtained include terminal and internal alkynes, as well as terminal alkenes, with yields ranging from 43% to 99%. Various tertiary silanes (Et3SiH, (EtO)(3)SiH, Ph3SiH) and the disubstituted silane Ph2SiH2 are suitable substrates for this reaction. The hydrosilylation reaction exhibits typical anti-Markovnikov regioselectivity, yielding mainly beta(E)-vinylsilanes from alkynes and linear alkyl silanes from alkenes.
APPLIED ORGANOMETALLIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Minghui Zhu, Peixin Wang, Qinglong Zhang, Wenjun Tang, Weiwei Zi
Summary: The aldol reaction is an important and versatile transformation in organic synthesis, but achieving stereoselectivity for the formation of diastereomeric products is challenging. In this study, a new catalytic system was developed to overcome the selectivity limitations of the reaction. Computational studies provided insights into the reaction mechanism and stereochemistry of the catalytic system.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Multidisciplinary
Wen-Wen Zhang, Bi-Jie Li
Summary: In this study, a new catalyst was developed for the enantioselective hydrosilylation of alkenes bearing a heteroatom substituent. Stereodivers synthesis could be achieved by regulating substrate geometry and ligand configuration.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Organic
Joshua A. Clarke, Art van der Est, Georgii Nikonov
Summary: The study presents a base-catalyzed hydrosilylation of nitriles to amines and esters to silylated alcohols, showing successful reactions in the presence of basic functional groups but failure for acidic substrates. Carbonyl functional groups, such as aldehydes, ketones, esters and carbamides, are reduced to corresponding alcohols and amines. Ester reduction can be selective in the presence of nitriles, but selectivity decreases for ester/carboxamide and carboxamide/nitrile pairs. Competitive experiments determined the preference in functional group reactivity as ester > carboxamide > nitrile.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2021)
