55638-25-0Relevant academic research and scientific papers
Preparation of polymer incarcerated gold nanocluster catalysts (PI-Au) and their application to aerobic oxidation reactions of boronic acids, alcohols, and silyl enol ethers
Miyamura, Hiroyuki,Yasukawa, Tomohiro,Kobayashi, Shu
, p. 6039 - 6049 (2015/03/30)
Heterogeneous gold nanocluster catalysts immobilized by the method known as polymer incarceration were prepared. Polystyrene-derived polymers with epoxide and alcohol moieties, which could be cross-linked under heating conditions, were employed as supports for their preparation. Cationic gold salts were reduced in a solution of NaBH4 and the polymers. Poor solvents for the polymers were added, and the polymers were precipitated and encapsulated gold nanoclusters with weak but multiple interactions between a gold nanocluster surface and the π electrons of benzene rings. The polymer capsules were heated under neat conditions to afford heterogeneous gold nanocluster catalysts; namely, polymer-incarcerated gold nanoclusters. The catalysts thus prepared could be applied to the aerobic oxidation of phenyl boronic acids, alcohols, and silyl enol ethers. We found that the choice of polymers, good and poor solvents for the polymers, metal loadings, heating conditions for cross-linking, and final activation were all crucial for obtaining high-activity catalysts.
A new zincate-mediated rearrangement reaction of 2-(1-hydroxyalkyl)-1- alkylcyclopropanol
Nomura, Kenichi,Matsubara, Seijiro
supporting information; scheme or table, p. 703 - 708 (2010/08/05)
A novel rearrangement of 2-(1-hydroxyalkyl)-1-alkylcyclopropanol has been found. It proceeds in the presence of a catalytic amount of organozinc ate complex to give vic-diols. The rearrangement can be applied to various types of 2-(1-hydroxyalkyl)-1-alkyl-cyclopropanol, which can be easily prepared from the corresponding α,β-ep-oxyketones and bis(iodozincio)methane. When bicyclo[13.1.0]-pentadecane-1, 15-diol was treated with the organozinc ate complex, the corresponding 14-membered cyclic vic-diol was obtained. Thus, this rearrangement is also useful for changing the ring size of cyclic substrates.
Reaction of carbonyl compounds with trialkylsilyl phenylselenide and tributylstannyl hydride under radical conditions
Nishiyama, Yutaka,Kajimoto, Hiroyuki,Kotani, Kazuya,Nishida, Takuma,Sonoda, Noboru
, p. 5696 - 5700 (2007/10/03)
A novel method for the hydrosilylation of carbonyl compounds has been developed. When carbonyl compounds were allowed to react with trimethylsilyl phenylselenide and tributylstannyl hydride in the presence of a catalytic amount of AIBN as the radical initiator, hydrosilylation of the carbonyl compounds efficiently proceeded to give the corresponding silyl ethers in moderate to good yields. In the absence of carbonyl compounds, the triethylsilyl hydride was obtained by the reaction of PhSeSiEt3 with Bu3SnH. Although the tributylgermyl phenylselenide instead of PhSeSiMe3 was treated with tributylstannyl hydride in the presence of a benzaldehyde under radical conditions, hydrogermylated product was not obtained and tributylgermyl hydride was mainly formed.
Hydrosilylation of carbonyl compounds using a PhSeSiMe3/Bu3SnH/AIBN system
Nishiyama, Yutaka,Kajimoto, Hiroyuki,Kotani, Kazuya,Sonoda, Noboru
, p. 3087 - 3089 (2007/10/03)
(equation presented) When carbonyl compounds were allowed to react with phenyl trimethylsilyl selenide and tributylstannyl hydride in the presence of a catalytic amount of AIBN as a radical initiator, the hydrosilylation of the carbonyl compounds efficiently proceeded to give the corresponding silyl ethers in moderate to good yields.
Competing, kc, Borderline, ks, and Carbonyl Addition Processes in Solvolyses of α-Keto Mesylates and Triflates. α-Keto Cations. 5
Creary, Xavier
, p. 5568 - 5577 (2007/10/02)
Solvolysis studies on tertiary α-keto mesylates show quite varying responses in rate to solvent ionizing power.The m values are 1.01 for 2-benzoyl-2-adamantyl mesylate (12), 0.66 for the mesylate derivative of 2-hydroxy-2,4,4-trimethyl-3-pentanone (4), and 0.63 for the mesylate derivative of 2-hydroxy-2-methylpropiophenone (3).The mesylate derivative of methyl α-hydroxyisobutyrate (5) does not correlate well with YOTs values, but instead it gives behavior that parallels that of isopropyl tosylate.Mesylates 3-5 solvolyze giving varying ratios of elimination and substitution products at rates comparable to that of isopropyl mesylate. β-d6 isotope effects for 3 and 4 range from 1.69 to 2.08 and are consistent with the intermediacy of α-keto cations. β-Deuterium isotope effects for 5 are quite variable (1.40-2.52) and parallel the amount of elimination product formed (22-94percent).This is consistent with the intermediacy of a reversibly formed ion-pair intermediate which can suffer proton loss.However, the SN2 (intermediate) mechanism remains a possibility in solvolyses of 5.Mesylate 3 solvolyzed in trifluoroethanol with added triethylamine to give an alkoxyoxirane.With small amounts of added 2,6-lutidine the 1,2-elimination product was major , while with added methanesulfonic acid the rearranged trifluoroethyl ester of dimethylphenyl acetic acid was major.These variable products were interpreted in terms of competing carbonyl addition processes and processes involving the α-keto cation.Secondary triflates derived from α-hydroxypropiophenone, 2,2-dimethyl-4-hydroxy-3-pentanone, and ethyl lactate solvolyzed giving the simple substitution product.Rates parallel solvent nucleophilicity and suggest a ks process involving negligible cationic character at the carbon α to the carbonyl group. kΔ processes are also not involved in solvolyses of these secondary triflates.
