32250-84-3Relevant academic research and scientific papers
Rhodium(I)-n-heterocyclic carbene-catalyzed addition of sodium tetraphenylborate to ketones to form tertiary alcohols
Yiit, Beyhan,Yiit, Murat,?zdemir, Ismail
, p. 2562 - 2571 (2014)
Rhodium complexes ([Rh(COD)(NHC)Cl]) were synthesized by the reaction of bis(1,3-dialkylperhydrobenzimidazolin-2-ylidene) with [RhClCOD]2 in toluene and characterized by elemental analysis, 1H NMR, 13C NMR and IR spectroscopy. These complexes were used as catalysts for the addition of sodium tetraphenylborate to aromatic ketones and corresponding tertiary alcohols were obtained in good yields.
Iridium-Catalyzed C(sp3)?H Addition of Methyl Ethers across Intramolecular Carbon–Carbon Double Bonds Giving 2,3-Dihydrobenzofurans
Ohmura, Toshimichi,Kusaka, Satoshi,Torigoe, Takeru,Suginome, Michinori
, p. 4448 - 4453 (2019/09/16)
Intramolecular addition of an O-methyl C(sp3)?H bond across a carbon-carbon double bond occurs in the iridium-catalyzed reaction of methyl 2-(propen-2-yl)phenyl ethers. The Ir/(S)-DTBM-SEGPHOS catalyst promotes the reaction efficiently in toluene at 110–135 °C to afford 3,3-dimethyl-2,3-dihydrobenzofurans. Enantioselective C(sp3)?H addition is achieved in the reaction of methyl 2-(1-siloxyethenyl)phenyl ethers, affording enantioenriched 3-hydroxy-2,3-dihydrobenzofuran derivatives with up to 96% ee. (Figure presented.).
Iodine-catalyzed transformation of aryl-substituted alcohols under solvent-free and highly concentrated reaction conditions
Jereb, Marjan,Vra?i?, Dejan
, p. 747 - 762 (2018/01/17)
Iodine-catalyzed transformations of alcohols under solvent-free reaction conditions (SFRC) and under highly concentrated reaction conditions (HCRC) in the presence of various solvents were studied in order to gain insight into the behavior of the reaction intermediates under these conditions. Dimerization, dehydration and substitution were the three types of transformations observed with benzylic alcohols. Dimerization and substitution reactions were predominant in the case of primary- and secondary alcohols, whereas dehydration prevailed in the case of tertiary alcohols. The relative reactivity of substituted 1-phenylethanols in I2-catalyzed dimerization under SFRC provided a good Hammett plot ρ+ = -2.8 (r2 = 0.98), suggesting the presence of electron-deficient intermediates with a certain degree of developed charge in the rate-determining step.
Introducing deep eutectic solvents to polar organometallic chemistry: Chemoselective addition of organolithium and grignard reagents to ketones in air
Vidal, Cristian,Garcia-Alvarez, Joaquin,Hernan-Gomez, Alberto,Kennedy, Alan R.,Hevia, Eva
supporting information, p. 5969 - 5973 (2014/06/10)
Despite their enormous synthetic relevance, the use of polar organolithium and Grignard reagents is greatly limited by their requirements of low temperatures in order to control their reactivity as well as the need of dry organic solvents and inert atmosphere protocols to avoid their fast decomposition. Breaking new ground on the applications of these commodity organometallics in synthesis under more environmentally friendly conditions, this work introduces deep eutetic solvents (DESs) as a green alternative media to carry out chemoselective additions of ketones in air at room temperature. Comparing their reactivities in DES with those observed in pure water suggest that a kinetic activation of the alkylating reagents is taking place, favoring nucleophilic addition over the competitive hydrolysis, which can be rationalized through formation of halide-rich magnesiate or lithiate species. Turning lithium green: A new protocol for the selective addition of Grignard and organolithium reagents to ketones in green, biorenewable, and deep eutectic solvents (DESs) is reported. The protocol establishes a bridge between main-group organometallic compounds and green solvents (ChCl=choline chloride; see picture). The DESs are superior reaction media for highly polar organometallic compounds.
Highly enantioselective arylation of aldehydes and ketones using AlArEt2(THF) as aryl sources
Zhou, Shuangliu,Wu, Kuo-Hui,Chen, Chien-An,Gau, Han-Mou
supporting information; experimental part, p. 3500 - 3505 (2009/09/30)
A series of AlArEt2(THF) (Ar = Ph (la), 4-MeC6H 4 (1b), 4-MeOC6H 4 (1c), 4-Me 3SiC6H4 (1d), 2-naphthyl (le)) were synthesized from reactions of AlEt2Br(THF) with ArMgBr. In CDC13 solution, the 1H NMR spectra showed that AlArEt2(THF) compounds exist as a mixture of four species of formulas of AlAr xEt3-x (THF) (x = 0, 1, 2, or 3). AlArEt2(THF) compounds were found to be superior and atom-economic reagents for asymmetric aryl additions to organic carbonyls. Aryl additions of AlArEt2(THF) to aldehydes catalyzed by the titanium(IV) complex of (R)-H8-BINOL were efficient with a short reaction time of 1 h, affording aryl addition products as exclusive or main products in high yields and excellent enantioselectivities of up to 98% ee. Although ethyl additions to aldehydes occurred in minor extent, this study demonstrates that increasing the amount of AlArEt2(THF) from 1.2 to 1.4 or to 1.6 equiv significantly improved the aryl addition products of up to >99%. On the other hand, asymmetric arylations of AlArEt2(THF) to ketones employing a titanium(IV) catalyst of (S)-BINOL produced optically active tertiary alcohols exclusively in excellent enantioselectivities of up to 94% ee.
A new aspect of magnesium bromide-promoted enantio-selective aryl additions of triaryl(tetrahydrofuran)aluminum to ketones catalyzed by a titanium(IV) catalyst of trans-1,2-bis(hydroxycamphorsulfonylamino)cyclohexane
Chen, Chien-An,Wu, Kuo-Hui,Gau, Han-Mou
scheme or table, p. 1626 - 1634 (2009/07/01)
A novel aspect of MgBr2-promoted asymmetric triarylaluminum- tetrahydrofuran [AlAr3 (THF)] additions to ketones catalyzed by a titanium catalyst of 20 mol% trans-1,2-bis(hydroxycamphorsulfonylamino) cyclohexane (2) is reported. The catalytic system works excellently for aromatic ketones with either an electron-withdrawing or an electrondonating substituent on the aromatic ring at the 2′-, 3′-, or 4′-positions, affording tertiary alcohols in excellent enantioselectivities of ≥90% ee, except for the cases of phenyl addition to 2′-methoxyacetophenone and 4-trimethylsilylphenyl (4-TMSC6H4) addition to acetopheneone.
