3021-89-4Relevant academic research and scientific papers
Alkylation of Lithium Trialkylalkynylborates with Benzo-1,3-dithiolium Fluoroborate
Pelter, Andrew,Rupani, Pushpa,Stewart, Peter
, p. 164 - 165 (1981)
Lithium trialkylalkynylborates react in a stereoselective fashion with benzo-1,3-dithiolium fluoroborate to give vinylboranes which on oxidation yield protected 3-oxo-aldehydes and on hydrolysis give protected αβ-unsaturated aldehydes; the hydrolysis is highly selective giving rise eventually to stereospecifically defined αβ-unsaturated aldehydes by a novel process.
Aldol Condensations on Solid Catalysts: A Cooperative Effect between Weak Acid and Base Sites
Climent,Corma,Fornes,Guil-Lopez,Iborra
, p. 1090 - 1096 (2002)
An amorphous aluminophosphate (ALPO) catalyst containing weak acid and base centers can carry out the aldol condensation of heptanal with benzaldehyde at much higher rates and selectivities than conventional solid acid (amorphous or crystalline aluminosil
Ir(NHC)-Catalyzed Synthesis of β-Alkylated Alcohols via Borrowing Hydrogen Strategy: Influence of Bimetallic Structure
Sung, Kihyuk,Lee, Mi-hyun,Cheong, Yeon-Joo,Kim, Yu Kwon,Yu, Sungju,Jang, Hye-Young
supporting information, p. 3090 - 3097 (2021/05/10)
Multi N-heterocyclic carbene(NHC)-modified iridium catalysts were employed in the β-alkylation of alcohols; dimerization of primary alcohols (Guerbet reaction), cross-coupling of secondary and primary alcohols, and intramolecular cyclization of alcohols. Mechanistic studies of Guerbet reaction, including kinetic experiments, mass analysis, and density functional theory (DFT) calculation, were employed to explain the fast reaction promoted by bimetallic catalysts, and the dramatic reactivity increase of monometallic catalysts at the late stage of the reaction. (Figure presented.).
Controlled Relay Process to Access N-Centered Radicals for Catalyst-free Amidation of Aldehydes under Visible Light
Chang, Sukbok,Jeon, Hyun Ji,Jung, Hoimin,Kim, Dongwook,Lee, Wongyu,Seo, Sangwon
supporting information, p. 495 - 508 (2021/01/28)
Nitrogen-centered radicals have attracted increasing attention as a versatile reactive intermediate for diverse C–N bond constructions. Despite the significant advances achieved in this realm, the controllable formation of such species under catalyst-free conditions remains highly challenging. Here, we report a new relay process involving the slow in situ generation of a photoactive N-chloro species via C–N bond formation, which subsequently enables mild and selective access to N-centered radicals under visible light conditions. The utility of this approach is demonstrated by the conversion of aldehydes to amides, employing N-chloro-N-sodio carbamates as a practical amidating source. This synthetic operation obviates the need for catalysts, external oxidants, and coupling reagents that are typically required in related processes, consequently allowing high functional group tolerance and excellent applicability for late-stage functionalization. Amides are an important class of structural motifs prevalently found in bioactive compounds and synthetic materials of great significance. Amidation of aldehydes has been established as an atom-efficient strategy for amide synthesis; however, current methods lack in applicability mainly due to the requirement of troublesome reagents. In this article, we describe an unconventional relay process to convert aldehydes to amides under catalyst-, oxidant-, and coupling-reagent-free conditions, which is enabled by the development of a new mechanistic platform that gives efficient and controllable access to N-centered radicals under visible light. A wide range of (hetero)aromatic and aliphatic aldehydes can be employed, including those derived from biologically relevant complex molecules. We anticipate that the accomplished methodological advances, combined with the unique mechanistic features, will lead to the widespread application of the present strategy in broad research fields. A catalyst-free approach for controlled access to N-centered radicals is described, which enables the conversion of aldehydes to amides via an unconventional relay process harnessing visible light. The key tactic relies on the use of photostable N-chloro-N-sodio-carbamate amidating reagent that leads to slow incorporations of a photoactive radical source via C–N formation and other involved intermediates thereafter. This methodology displays excellent applicability and sustainable chemistry credentials and, thus, holds a promise for finding broad applications.
1,3-Dibromo-5,5-dimethylhydantoin as a Precatalyst for Activation of Carbonyl Functionality
?ebular, Klara,Bo?i?, Bojan ?.,Stavber, Stojan
supporting information, (2019/08/01)
Activation of carbonyl moiety is one of the most rudimentary approaches in organic synthesis and is crucial for a plethora of industrial-scale condensation reactions. In esterification and aldol condensation, which represent two of the most important reactions, the susceptibility of the carbonyl group to nucleophile attack allows the construction of a variety of useful organic compounds. In this context, there is a constant need for development of and improvement in the methods for addition-elimination reactions via activation of carbonyl functionality. In this paper, an advanced methodology for the direct esterification of carboxylic acids and alcohols, and for aldol condensation of aldehydes using widely available, inexpensive, and metal-free 1,3-dibromo-5,5-dimethylhydantoin under neat reaction conditions is reported. The method is air- and moisture-tolerant, allowing simple synthetic and isolation procedures for both reactions presented in this paper. The reaction pathway for esterification is proposed and a scale-up of certain industrially important derivatives is performed.
Method for preparing high-carbon branched-chain secondary alcohol
-
Paragraph 0074; 0075, (2019/10/01)
The invention relates to a method for preparing high-carbon branched-chain secondary alcohol. The method comprises the steps: preparing branched-chain olefin aldehyde through self-condensation of linear aliphatic aldehyde or branched-chain aliphatic aldehyde without tertiary carbon, performing a gas-liquid heterogeneous condensation reaction on the branched-chain olefin aldehyde and aliphatic ketone without tertiary carbon under the catalysis action of organic base so as to prepare branched-chain dienone, and performing hydrogenation on the branched-chain dienone so as to prepare unsaturated or saturated branched-chain secondary alcohol. The method has wide sources of raw materials and low cost, and the product has a certain structure, and is particularly suitable for preparation of secondary alcohol polyoxyethylene ether and secondary alcohol polyoxyethylene ether derivatives which have narrow molecular weight distribution; and the alcoholic hydroxyl group of the product is secondary alcohol which has a branched-chain structure but no tertiary carbon, the low temperature performance is excellent, and the biodegradability is good.
Synthesis of Guerbet ionic liquids and extractants as β-branched biosourceable hydrophobes
Damilano, Giacomo,Binnemans, Koen,Dehaen, Wim
supporting information, p. 9778 - 9791 (2019/12/02)
This study investigates the synthesis of β-branched amines and β-branched quaternary ammonium chloride ionic liquids as novel extractants. The synthesis methodology was tailored to facilitate the reaction scale-up and the use of biorenewable starting materials. The developed process is an overall green, easy and straightforward synthesis of β-branched amines, and ammonium salts, starting from linear aldehydes. In order to evaluate the potential of the synthesised materials in applications, the rheology, density, thermal stability, chemical stability, phase transitions, and mutual solubility with water of the novel extractants was studied.
Acid Catalysts Based on Mesoporous Aromatic Frameworks in Aldol Condensation of Furfural with Some Carbonyl Compounds
Talanova, M. Yu.,Yarchak,Karakhanov
, p. 857 - 864 (2019/08/12)
Aldol condensation of furfural with acetone and a series of aldehydes in the presence of PAF-SO3H acid catalyst based on mesoporous aromatic frameworks was investigated. The reaction course depending on the process temperature, catalyst amount, and reactant ratio was considered for the furfural condensation with acetone as an example. The catalyst can be reused in several cycles without appreciable activity loss.
Vanadium-Catalyzed Condensation of Ethyl Cyanoacetate with Ketones
Khusnutdinov,Shchadneva,Mayakova, Yu. Yu.
, p. 403 - 409 (2018/04/24)
Vanadium compounds and complexes activated by pyridine or morpholine catalyze condensation of ethyl cyanoacetate with ketones and aldehydes leading to alkylidenecyanoacetates in 75–100% yield.
Acylation of dimethyl maleate photocatalyzed by decatungstate anion: insights into the hydrogen atom transfer reaction mechanism
Martínez, Juan Pablo,Rivera-Avalos, Ernesto,Vega-Rodríguez, Sarai,de Loera, Denisse
, p. 2061 - 2073 (2017/12/06)
Polyoxometalates arise as significant catalysts in the field of organic chemistry due to their diverse properties and functions. Recent progress based on experimental evidence and density functional theory (DFT) calculations provides valuable information to demystify the chemistry of decatungstate anion, W10O32 4?. Particularly, functionalization of aldehydes by homolytic C–H bond cleavage can be efficiently achieved when it is catalyzed by this polyoxometalate. Two reaction mechanisms have been formulated to account for the role of W10O32 4? in organic chemical reactions: the single electron transfer and the hydrogen atom transfer (HAT) mechanisms. In this contribution, the HAT pathway for the acylation of dimethyl maleate is experimentally and quantum-chemically explored in detail. Results based on DFT calculations under the unrestricted formalism suggest that the acylation occurs in a barrierless process upon the formation of the lowest-in-energy triplet excited state of W10O32 4?. These outcomes agree well with the experimental evidence since the acylated adduct was produced at a 90% yield; in this regard, side reactions like radical couplings and decarbonylation resulted in less competitiveness. The current work may therefore help in the comprehension of the mechanistic details leading to the synthesis of organic compounds photocatalyzed by polyoxometalates, even under solar radiation.
