37854-36-7Relevant academic research and scientific papers
Fast Addition of s-Block Organometallic Reagents to CO2-Derived Cyclic Carbonates at Room Temperature, Under Air, and in 2-Methyltetrahydrofuran
Elorriaga, David,de la Cruz-Martínez, Felipe,Rodríguez-álvarez, María Jesús,Lara-Sánchez, Agustín,Castro-Osma, José Antonio,García-álvarez, Joaquín
, p. 2084 - 2092 (2021/04/02)
Fast addition of highly polar organometallic reagents (RMgX/RLi) to cyclic carbonates (derived from CO2 as a sustainable C1 synthon) has been studied in 2-methyltetrahydrofuran as a green reaction medium or in the absence of external volatile organic solvents, at room temperature, and in the presence of air/moisture. These reaction conditions are generally forbidden with these highly reactive main-group organometallic compounds. The correct stoichiometry and nature of the polar organometallic alkylating or arylating reagent allows straightforward synthesis of: highly substituted tertiary alcohols, β-hydroxy esters, or symmetric ketones, working always under air and at room temperature. Finally, an unprecedented one-pot/two-step hybrid protocol is developed through combination of an Al-catalyzed cycloaddition of CO2 and propylene oxide with the concomitant fast addition of RLi reagents to the in situ and transiently formed cyclic carbonate, thus allowing indirect conversion of CO2 into the desired highly substituted tertiary alcohols without need for isolation or purification of any reaction intermediates.
Benzoxaborole Catalyst for Site-Selective Modification of Polyols
Kusano, Shuhei,Miyamoto, Shoto,Matsuoka, Aki,Yamada, Yuji,Ishikawa, Ryuta,Hayashida, Osamu
supporting information, p. 1598 - 1602 (2020/02/11)
The site-selective modification of polyols bearing several hydroxyl groups without the use of protecting groups remains a significant challenge in synthetic chemistry. To address this problem, novel benzoxaborole derivatives were designed as efficient catalysts for the highly site-selective and protecting-group-free modification of polyols. To identify the effective substituent groups enhancing the catalytic activity and selectivity, a series of benzoxaborole catalysts 1a–k were synthesized. In-depth analysis for the substituent effect revealed that 1i–k, bearing multiple electron-withdrawing fluoro- and trifluoromethyl groups, exhibited the greatest catalytic activity and selectivity. Moreover, 1i-catalyzed benzoylation, tosylation, benzylation, and glycosylation of various cis-1,2-diol derivatives proceeded with good yield and site-selective manner.
Chitosan-Silica Sulfate Nano Hybrid as a Novel and Highly Proficient Heterogeneous Nano Catalyst for Regioselective Ring Opening of Epoxides via Carboxylic Acids
Behrouz, Somayeh,Soltani Rad, Mohammad Navid,Piltan, Mohammad Amin,Doroodmand, Mohammad Mahdi
, (2017/09/19)
The synthesis and characterization of chitosan-silica sulfate nano hybrid (CSSNH) as a novel and efficient heterogeneous nano catalyst involving acid-base bifunctional activity is described. The catalytic potency and activity of this eco-friendly catalyst was investigated in regioselective ring opening of epoxides with carboxylic acids to access structurally diverse 1,2-diol mono-esters in good to excellent yields. CSSNH catalyst was characterized using different microscopic and spectroscopic techniques encompassing scanning electron microscopy, transmission electron microscopy, X-ray diffraction, N2 adsorption isotherm, and Fourier transform infrared spectroscopy. The green nature, cheapness, efficiency, ease of preparation, handling and reusability of this new catalyst makes this catalyst to be useful for green industrial processes.
Stereoinversion of Stereocongested Carbocyclic Alcohols via Triflylation and Subsequent Treatment with Aqueous N,N-Dimethylformamide
Ochiai, Hidenori,Niwa, Takashi,Hosoya, Takamitsu
supporting information, p. 5982 - 5985 (2016/12/09)
A convenient method for the stereoinversion of secondary alcohols, applicable to stereocongested carbocyclic substrates, is reported. A simple three-step procedure, including triflylation of the hydroxy group, nucleophilic oxygenative displacement by the treatment with aqueous N,N-dimethylformamide (DMF), and methanolysis, allowed for efficient stereoinversion of various substrates, including sugar derivatives, in one pot.
Radical Cyclization Followed by the Fragmentation of Carbonyl Compounds: Effect of an α-Benzoyl Group
Chien, Li-An,Chang, Che-Chien
, p. 11294 - 11301 (2015/12/01)
To study a recently developed radical cyclization reaction followed by a fragmentation process in more detail, a series of α-benzoyl carbonyl compounds were prepared, including precursors with aldehyde and ketone moieties. Initiated by tributyltin hydride
I2-catalyzed regioselective oxo- and hydroxy-acyloxylation of alkenes and enol ethers: A facile access to α-acyloxyketones, esters, and diol derivatives
Reddi, Rambabu N.,Prasad, Pragati K.,Sudalai, Arumugam
supporting information, p. 5674 - 5677 (2015/02/19)
I2-catalyzed oxo-acyloxylation of alkenes and enol ethers with carboxylic acids providing for the high yield synthesis of α-acyloxyketones and esters is described. This unprecedented regioselective oxidative process employs TBHP and Et3/s
Regioselective, borinic acid-catalyzed monoacylation, sulfonylation and alkylation of diols and carbohydrates: Expansion of substrate scope and mechanistic studies
Lee, Doris,Williamson, Caitlin L.,Chan, Lina,Taylor, Mark S.
supporting information; experimental part, p. 8260 - 8267 (2012/07/14)
Synthetic and mechanistic aspects of the diarylborinic acid-catalyzed regioselective monofunctionalization of 1,2- and 1,3-diols are presented. Diarylborinic acid catalysis is shown to be an efficient and general method for monotosylation of pyranoside derivatives bearing three secondary hydroxyl groups (7 examples, 88% average yield). In addition, the scope of the selective acylation, sulfonylation, and alkylation is extended to 1,2- and 1,3-diols not derived from carbohydrates (28 examples); the efficiency, generality, and operational simplicity of this method are competitive with those of state-of-the-art protocols including the broadly applied organotin-catalyzed or -mediated reactions. Mechanistic details of the organoboron-catalyzed processes are explored using competition experiments, kinetics, and catalyst structure-activity relationships. These experiments are consistent with a mechanism in which a tetracoordinate borinate complex reacts with the electrophilic species in the turnover-limiting step of the catalytic cycle.
Selective monobenzoylation of 1,2- and 1,3-diols catalyzed by Me 2SnCl2 in water (organic solvent free) under mild conditions
Muramatsu, Wataru,William, Julius M.,Onomura, Osamu
experimental part, p. 754 - 759 (2012/02/15)
We have developed an efficient method for selective monobenzoylation of 1,2- and 1,3-diols in water catalyzed by Me2SnCl2. Treatment of 1,2- and 1,3-diols with benzoyl chlorides, DMT-MM, and potassium carbonate in the presence of a catalytic amount of Me2SnCl 2 and DMAP in water at room temperature gave monobenzoates in up to 97% yield.
Borinic acid-catalyzed regioselective acylation of carbohydrate derivatives
Lee, Doris,Taylor, Mark S.
supporting information; experimental part, p. 3724 - 3727 (2011/05/14)
Reversible covalent interactions of organoboron compounds are exploited as the basis for regioselective borinic acid-catalyzed acylations of polyols. This catalytic protocol enables differentiation of the secondary OH groups of a wide range of carbohydrat
Selective mono-acylation of 1,2- and 1,3-diols using (α,α- difluoroalkyl)amines
Wakita, Natsumi,Hara, Shoji
experimental part, p. 7939 - 7945 (2010/10/19)
In the reaction of N,N-diethyl-α,α-difluorobenzylamine (DFBA) with 1,2- or 1,3-diols, selective mono-benzoylation occurs to afford mono-esters of the diols in good yield. The reaction is completed under mild conditions in a short reaction time. Further, prim-, sec-, and tert-diols and catechol can be converted to the corresponding mono-benzoates. DFBA is used for the protection of the hydroxy group in sugars. The selective mono-nicotinylation, formylation and pivaloylation of diols are also performed by using the corresponding difluoroalkylamines.
