37858-00-7Relevant academic research and scientific papers
Ionic Liquids with Multi-Active Sites Synergistically Catalyzed Metal-Free Transformation of Alcohols Using Dimethyl Carbonate as an Environmental Solvent
Li, Zengmin,Wen, Yating,Wang, Ning,Han, Feng,Li, Ying,Zhuang, Hongfeng,Miao, Chengxia
, p. 3819 - 3826 (2021/08/24)
One of the ultimate goals in organic synthesis is to develop metal-free, efficient and easily separable catalytic system for atom economic organic reactions in an environmental solvent. Direct substitution reaction of alcohols and hydrocarbon compounds is a significant and atom economic method for C?C bond formation. Herein, a metal-free and efficient catalytic system including recyclable pyridine-based ionic liquids with multiple active sites as the catalyst and dimethyl carbonate as the environmentally friendly solvent was developed for atom economic C3 substitution of 4-hydroxycoumarins with alcohols. Primary aromatic alcohols, secondary aliphatic and aromatic alcohols were suitable for the reaction, providing up to 99 % yield. The catalytic system could be easily scaled up to gram-scale with nearly quantitative yield. Coumatetralyl as commercial rodenticide could be prepared directly from commercially available 4-hydroxycoumarin and 1,2,3,4-tetrahydronaphthalen-1-ol. Racemic product derived from the reaction of (R)-1-phenylethanol and 4-hydroxycoumarin indicated the reaction was achieved through an SN1 pathway. The comparison of the activities and acidities of the ionic liquids demonstrated that there was no directly relationship between them. Control experiments showed that the reaction probably proceeded via carbocation, ether intermediate and synergistically promoted effect of hydrogen bonding between the ionic liquid with multi-active sites and substrates.
Nickel Catalyzed Intermolecular Carbonyl Addition of Aryl Halide
Ishida, Seima,Suzuki, Hiroyuki,Uchida, Seiichiro,Yamaguchi, Eiji,Itoh, Akichika
supporting information, p. 7483 - 7487 (2019/12/11)
In this study, we develop a nickel-catalyzed carbonyl arylation reaction employing aldehydes with aryl and allyl halides. Various aryl, α,β-unsaturated aldehyde and aliphatic aldehydes can be converted into their corresponding secondary alcohols in moderate-to-high yields. In addition, we extended this approach to develop an asymmetric reductive coupling reaction that combines nickel salts with chiral bisoxazoline ligands to give secondary alcohols with moderate enantioselectivity.
Direct halogenation of alcohols with halosilanes under catalyst- and organic solvent-free reaction conditions
Ajvazi, Njomza,Stavber, Stojan
, p. 2430 - 2433 (2016/05/19)
A chemoselective method for the direct halogenation of different types of alcohols with halosilanes under catalyst- and solvent-free reaction conditions (SFRC) is reported. Various primary, secondary and tertiary benzyl alcohols and tertiary alkyl alcohols were directly transformed to the corresponding benzyl and alkyl halides, respectively, using chlorotrimethylsilane (TMSCl) and bromotrimethylsilane (TMSBr).
Solvent control of product diversity in palladium-catalyzed addition of arylboronic acid to aryl aldehydes
Das, Tuluma,Chakraborty, Amarnath,Sarkar, Amitabha
supporting information, p. 5174 - 5178 (2014/12/10)
In Pd-catalyzed arylboronic acid addition to aryl aldehydes, the expected carbinol or asymmetrical ether can be obtained as the major product by altering aqueous solvent composition. Exploiting this methodology with 2-formylbiphenyls as reaction partner, a fluorene scaffold can be readily constructed in two steps.
Iodine-catalyzed disproportionation of aryl-substituted ethers under solvent-free reaction conditions
Jereb, Marjan,Vrazic, Dejan
, p. 1978 - 1999 (2013/05/22)
Iodine was demonstrated to be an efficient catalyst for disproportionation of aryl-substituted ethers under solvent-free reaction conditions. Variously substituted 1,1,1′,1′-tetraaryldimethyl ethers were transformed into the corresponding diarylketone and diarylmethane derivatives. I 2-catalyzed transformation of 4-methoxyphenyl substituted ethers yielded mono- and dialkylated Friedel-Crafts products as well. Treatment of trityl alkyl and trityl benzyl ethers with a catalytic amount of iodine produced triphenylmethane and the corresponding aldehydes and ketones. The electron-donating substituents facilitated the reaction, while the electron-withdrawing groups retarded it; the difference in reactivity is not very high. Such an observation may be in favour of hydride transfer, predominantly from the less electron rich side of the ether with more stable carbocation formation. With the isotopic studies it was established that a substantial portion of the C-H bond scission took place in the rate-determining step, while the carbonyl oxygen atom originated from the starting ether, and not from the air. The transformation took place under air and under argon, and HI was not a functioning catalyst.
Sulfonic acid-functionalized ionic liquids as metal-free, efficient and reusable catalysts for direct amination of alcohols
Han, Feng,Yang, Lei,Li, Zhen,Xia, Chungu
experimental part, p. 1052 - 1060 (2012/05/21)
A series of sulfonic acid-functionalized (SO3H-functionalized) ionic liquids was synthesized and used as metal-free, highly selective and efficient catalysts for the direct amination of alcohols. Notably, the activities of the series of SO3H-functionalized ionic liquids were compared and a 92% isolated yield was obtained using 3-tetradecyl-1-(butyl-4- sulfonyl)imidazolium trifluoromethanesulfonate ([BsTdIM][OTf]) as the catalyst. Importantly, the catalytic system has wide substrate scope including benzylic, allyl, propargylic, aliphatic alcohols with sulfonamide, amide, carbamate, aromatic amine and N-heterocyclic compounds. Interestingly, the system was also suitable for a multi-gram scale direct amination of alcohols. Additionally, the reusable nature of [BsTdIM][OTf] makes this protocol more attractive and avoids the disposal and neutralization of acidic catalysts. Moreover, preliminary experiments indicated that this reaction should proceed via an SN1 pathway. Copyright
EWG assisted nucleophilic fluorination using PPHF: A strategy for the synthesis of 1,2,2-triaryl-2-fluoroethanones
Kumar, Anil,Pal, Anil K.,Anand, Rishi D.,Singh, Tej V.,Venugopalan, Paloth
experimental part, p. 8308 - 8313 (2011/11/12)
The nucleophilic fluorination of 1,2,2-triaryl-2-hydroxyethanones by fluoride ion has been carried out using pyridinium poly(hydrogen fluoride) (PPHF) to give 1,2,2-triaryl-2-fluoroethanones in fairly good yield. The presence of electron withdrawing group
Organic reactions catalyzed by methylrhenium trioxide: Dehydration, amination, and disproportionation of alcohols
Zhu, Zuolin,Espenson, James H.
, p. 324 - 328 (2007/10/03)
Methylrhenium trioxide (MTO) is the first transition metal complex in trace quantity to catalyze the direct formation of ethers from alcohols. The reactions are independent of the solvents used: benzene, toluene, dichloromethane, chloroform, acetone, and in the alcohols themselves. Aromatic alcohols gave better yields than aliphatic. Reactions between two different alcohols could also be used to prepare unsymmetric ethers, the best yields being obtained when one of the alcohols is aromatic. MTO also catalyzes the dehydration of alcohols to form olefins at room temperature, aromatic alcohols proceeding in better yield. When primary (secondary) amines were used as the limiting reagent, direct amination of alcohols catalyzed by MTO gave good yields of the expected secondary (tertiary) amines at room temperature. Disproportionation of alcohols to alkanes and carbonyl compounds was also observed for aromatic alcohols in the presence of MTO. On the basis of the results of this investigation and a comparison with the interaction between MTO and water, a concerted process and a mechanism involving carbocation intermediates have been suggested.
Evidence for rate limiting C-H bond cleavage in the leuckart reaction
Awachie, Peter I.,Agwada, Vincent C.
, p. 1899 - 1910 (2007/10/02)
A rho value of +0.21 is reported for the reaction of mono 4-substi- tuted benzophenones with formamide. This, in conjunction with a kinetic iso- tope effect value of 1.80 obtained for the system, suggests a rate-limiting C-H bond cleavage.
Efficient Solid-state Reactions of Alcohols: Dehydration, Rearrangement, and Substitution
Toda, Fumio,Takumi, Hideaki,Akehi, Masafumi
, p. 1270 - 1271 (2007/10/02)
Dehydration, rearrangement, and substitution reactions of alcohols occur more efficiently in the solid state than in solution.
