Spelling suggestions: "subject:"catalysis"" "subject:"atalysis""
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Catalysts for the electromotive activation of oxygen in alkaline media /Humphrey, Raymond Arthur January 1955 (has links)
No description available.
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Part I. Development and characterization of a palladium hydrogenation system. ; Part II. Synthesis and metabolism of [epsilon]-N-methyllysines /Elamin, Babiker Ali Mohamed January 1980 (has links)
No description available.
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Catalysis in peptide chemistry /Coleman, Daniel Raymond January 1981 (has links)
No description available.
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Electrocatalysis with platinum and modified carbon electrodes /Kao, Wen-Hong January 1984 (has links)
No description available.
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Dynamic absorption and desorption studies on a reactive system : t-Butyl Alcohol - Water - Isobutylene - Alumina /Haering, Edwin Raymond January 1966 (has links)
No description available.
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Bifunctional catalysis of [alpha]-hydrogen exchange in isobutyraldehyde-2? by 1-dimethylamino-8-amino-2-octyne /Lynn, Jesse Lynch January 1971 (has links)
No description available.
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Separation of Piperylene Concentrate via Metathesis CatalysisAllred, Donald R. 01 October 1982 (has links) (PDF)
Diolefin metathesis, using a Re2O7 catalyst, failed to show a reactivity difference due to conjugation of double bonds. However, the same system allows reaction of pentadiene while not affecting cyclopentene yielding a successful reaction ΓÇô separation scheme for a piperylene concentrate mixture.
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A Two Part Research Report: Aromatic Nucelophilic Fluoroal Koxylation via Cationic Phase Transfer Catalysis and Reactions of Unsymmetrical Vinamidinium Salts with Organometallic ReagentsCoury, Joseph E. 01 January 1984 (has links) (PDF)
This report discusses research which was conducted in two areas: the study of aromatic nucleophilic fluoroalkoxylation assisted via cationic phase transfer catalysis and the study of unsymmetrical vinamidinium salts and their reactions with organometallic reagents.
Sodium alkoxides have been successfully used to fluoroalkoxylate activated halo- aryl and heteroaryl substrates under phase transfer catalysis conditions. Optimum reaction conditions incorporated tetra-n-butyl-phosphonium bromide as the catalyst and refluxing toluene as the solvent medium. Different quarternary phosphonium and arrmonium salts have been evaluated as catalysts: also, the effects of activating groups, leaving groups, and nucleophiles have been reported.
The reaction of 3-dimethylamino-3-phenyl-prop-2-en-l-ylidendimethyliminium perchlorate with organolithium and Grignard reagents has also been studied in an effort to define the reaction in terms of which electrophilic site of the salt is susceptible to nucleophilic attack to the greatest extent. The results reported reveal that the reaction occurs at the 1-position in all cases producing the α, β-unsaturated ketone after acid hydrolysis.
Finally, this report reveals the experimental procedures used as well as the spectral and physical data of all new compounds synthesized. Explanations of the data are offered and recommendations for future research in both areas are given.
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Catalytic Enantioselective Synthesis of Secondary Organoboronates and Progress Towards the Total Synthesis of Sarcodictyins:Hu, Weipeng January 2022 (has links)
Thesis advisor: James P. Morken / This dissertation will present three main projects focusing on the transition metal-catalyzed enantioselective synthesis of secondary organoboronic esters and progress towards the total synthesis of sarcodictyins. In the first project, a palladium-catalyzed enantioselective conjunctive cross-coupling reaction with propargylic electrophiles will be described. The tetra-substituted allenes are isolated with good yield and enantioselectivity and the beneficial effects of alcohol additives are investigated. The second project describes the enantioselective synthesis of ɑ-boryl zinc reagents by a nickel-catalyzed carbozincation reaction. The in situ generated ɑ-boryl zinc intermediate can be trapped by copper-mediated allylations, palladium-catalyzed Negishi cross-couplings, and cerium-mediated halogenation reactions to construct various chiral organoboranes. The synthetic utility of this methodology is showcased by the synthesis of natural products, including bruguierol A, (-)-aphanorphine, and (-)-enterolactone. The mechanism is studied with the assistance of EPR and deuterium-labeling experiments and a catalytic cycle through a Ni(I) intermediate is proposed. The third project depicts a synthetic route to essential precursors in the progress of the total synthesis of sarcodictyins. Various attempts to construct the ten-membered ring core of sarcodictyin have been made, including Sonogashira reaction, Dieckmann condensation, and lithium—halogen exchange process. / Thesis (PhD) — Boston College, 2022. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Chemistry.
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Cp*M-Mediated P-H Activation Reactions: Activity and MechanismsYang, Jin 22 September 2022 (has links)
This thesis presented the synthesis and reactivity of metal complexes for the
hydrophosphination of alkenes and dehydrocoupling of phosphines. The mechanism of
these metal-catalyzed P-H activation reactions was explored. Half-sandwich Cp*Ru complexes (Cp*= 1,2,3,4,5-pentamethylcyclopentadienyl)
were developed as catalysts for hydrophosphination, based on the previous work in the
Rosenberg group. Cp*Ru phosphido complexes, Ru(h 5 -Cp*)(PR2 )(PR2 H)2 (Ru-1) were
found to be the vital intermediates for the hydrophosphination. Preliminary mechanistic
studies also indicate that the catalyst resting state is Ru(h5 -Cp*)(PR2 )(PR2 H)(P) (P =
hydrophosphination product) and intramolecular P-H bond cleavage is turnover-limiting.
These investigations provide sufficient parallels to our established chemistry of the indenyl
analogues to imply that conjugate addition of metal phosphido at alkene plays a significant
role in these half-sandwich catalytic systems. The increased steric crowding at the Cp*Ru
fragment and P-basicity/nucleophilicity of its phosphido complexes lead to a 30-fold
increase in the hydrophosphination activity in the Cp* system compared to the indenyl
catalysts.
A half-sandwich Co catalyst, Co(h 5 -Cp*)I 2 (CO) (Co-1), was also developed for
hydrophosphination along the lines of the conjugate addition mechanism. Similar to the
Cp*Ru system, the substrate scope for alkene is limited to electron-deficient alkene.
However, the Cp*Co catalyst significantly expands the substrate scope for phosphines
(PR2 H and PRH 2 , R = alkyl and aryl). A detailed mechanistic study on the Cp*Co system
was performed. The results show that the Co-catalyzed hydrophosphination occurs through
iv
an outer-sphere mechanism and the stoichiometric formation of diphosphine is a critical
catalyst activation step.
Since the side product diphosphine was formed during the Co-catalyzed
hydrophosphination, using complex Co-1 as a catalyst for dehydrocoupling phosphines
was investigated. The preliminary studies reveal the role of base and Cp* ligand in the
catalysis. Additionally, the study highlights the importance of removing dihydrogen
throughout the process. Thus, hydrogen acceptors (HA) were used to facilitate the
dehydrocoupling reactions. Last, the novel P-H activation process between Cp*Co
complexes [Co(h5 -Cp*)(NCCH 3 ) 3 ][SbF 6 ] 2 (Co-5) and excess PPh2 H was investigated
through various analytical techniques. / Graduate / 2023-09-08
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