Lecture Notes Chem 51B S. King Chapter 9 Alcohols, Ethers, and
... group (an alcohol) at the carbon undergoing nucleophilic attack. This is especially important when the nucleophile is a weak nucleophile (such as an alcohol or water.) ...
... group (an alcohol) at the carbon undergoing nucleophilic attack. This is especially important when the nucleophile is a weak nucleophile (such as an alcohol or water.) ...
Part I Carbohydrate Auxiliaries - Wiley-VCH
... (modified Strecker reaction) are fundamental carbon–carbon bond-forming processes [3], which are efficient methods for preparing α-amino acids (Scheme 1.1). In 1987 Kunz and coworkers first reported pivaloyl protected d-galactosyl amine 3 as a very useful tool for asymmetric aminonitrile syntheses [4]. ...
... (modified Strecker reaction) are fundamental carbon–carbon bond-forming processes [3], which are efficient methods for preparing α-amino acids (Scheme 1.1). In 1987 Kunz and coworkers first reported pivaloyl protected d-galactosyl amine 3 as a very useful tool for asymmetric aminonitrile syntheses [4]. ...
Full-Text PDF
... catalytically active 14e species II, which is placed 12.6 kcal/mol above I, requiring the overcoming of a barrier of 22.5 kcal/mol. Bearing a low barrier of 4.9 kcal/mol, the relative low stability of species II assists the next olefin coordination to the metal center to give the intermediate III, w ...
... catalytically active 14e species II, which is placed 12.6 kcal/mol above I, requiring the overcoming of a barrier of 22.5 kcal/mol. Bearing a low barrier of 4.9 kcal/mol, the relative low stability of species II assists the next olefin coordination to the metal center to give the intermediate III, w ...
Modern Synthetic Methods for Copper-Mediated C(aryl
... ethers, diaryl amines, or diaryl thioethers): The formation of a C(aryl)O, a C(aryl)N, or a C(aryl)S bond by the reaction of an aryl halide with a phenol, an aniline, or a thiophenol, respectively, mediated (originally catalytic) by a copper species [Eq. (4)]. ...
... ethers, diaryl amines, or diaryl thioethers): The formation of a C(aryl)O, a C(aryl)N, or a C(aryl)S bond by the reaction of an aryl halide with a phenol, an aniline, or a thiophenol, respectively, mediated (originally catalytic) by a copper species [Eq. (4)]. ...
Boron Reagents in Process Chemistry: Excellent
... Dialkoxyboranes can also be used in hydroboration reactions generally at higher temperatures than borane complexes. These compounds are prepared via reaction of a borane complex and a diol, such as pinacol and catechol. Transition metal catalyzed hydroboration with catecholborane (CATB) and pinacolb ...
... Dialkoxyboranes can also be used in hydroboration reactions generally at higher temperatures than borane complexes. These compounds are prepared via reaction of a borane complex and a diol, such as pinacol and catechol. Transition metal catalyzed hydroboration with catecholborane (CATB) and pinacolb ...
Elimination Reactions
... • E1 reactions occur under essentially neutral conditions with polar solvents, such as water, ethyl alcohol or acetic acid. • E1 reactions can also occur with strong bases, but only at low concentration, about 0.01 to 0.1 M or below. • E2 reactions require strong base in high concentration, about 1 ...
... • E1 reactions occur under essentially neutral conditions with polar solvents, such as water, ethyl alcohol or acetic acid. • E1 reactions can also occur with strong bases, but only at low concentration, about 0.01 to 0.1 M or below. • E2 reactions require strong base in high concentration, about 1 ...
R - Evans - Harvard University
... be attractive precursors to enantiomerically pure a-amino acids if effective electrophilic aminating agents could be developed. The simple strategy that was envisioned (Scheme 11) held the potential for a useful collection of desirable features, making it complementary to existing methodologies. Fir ...
... be attractive precursors to enantiomerically pure a-amino acids if effective electrophilic aminating agents could be developed. The simple strategy that was envisioned (Scheme 11) held the potential for a useful collection of desirable features, making it complementary to existing methodologies. Fir ...
Name_____________________________________ 22 • Organic
... is added. The resulting product will react with a base to form a salt and water. When the new product in container X is mixed with container Y and H2SO4 is added, the chemist is able to confirm that: ...
... is added. The resulting product will react with a base to form a salt and water. When the new product in container X is mixed with container Y and H2SO4 is added, the chemist is able to confirm that: ...
研 究 業 績 リ ス ト
... H. Matsuzaka, J.-P. Qü, T. Ogino, M. Nishio, Y. Nishibayashi, Y. Ishii, S. Uemura, M. Hidai J. Chem. Soc., Dalton Trans., 4307-4312 (1996). (26) Palladium-catalyzed Homocoupling Reactions of Organic Tellurides Y. Nishibayashi, C. S. Cho, K. Ohe, S. Uemura J. Organomet. Chem., 526, 335-339 (1996). (2 ...
... H. Matsuzaka, J.-P. Qü, T. Ogino, M. Nishio, Y. Nishibayashi, Y. Ishii, S. Uemura, M. Hidai J. Chem. Soc., Dalton Trans., 4307-4312 (1996). (26) Palladium-catalyzed Homocoupling Reactions of Organic Tellurides Y. Nishibayashi, C. S. Cho, K. Ohe, S. Uemura J. Organomet. Chem., 526, 335-339 (1996). (2 ...
CH221 CLASS 13
... Hydration of Alkenes Addition of water to alkenes to give alcohols is one of the most important reactions of alkenes. In industry, this is accomplished by the use of strong acid catalysts and high temperatures, but this is not really of much value in the laboratory. However, tertiary alcohols can b ...
... Hydration of Alkenes Addition of water to alkenes to give alcohols is one of the most important reactions of alkenes. In industry, this is accomplished by the use of strong acid catalysts and high temperatures, but this is not really of much value in the laboratory. However, tertiary alcohols can b ...
Organic Chemistry
... Because tertiary and secondary carbocations are more stable than primary carbocations, Markovnikov addition is observed in the electrophilic addition of HX to alkenes, so the product formed is the one with the halogen substituent upon the more highly substituted carbon. Also, rearrangement (hydride ...
... Because tertiary and secondary carbocations are more stable than primary carbocations, Markovnikov addition is observed in the electrophilic addition of HX to alkenes, so the product formed is the one with the halogen substituent upon the more highly substituted carbon. Also, rearrangement (hydride ...
NAME - HCC Learning Web
... ____3. Which of the following statement is(are) correct? A. the maximum number of electrons possible for a set of p-orbitals is 6? B. the ground state electron configuration of carbon 1s2 2s2 2px1 2py1 2pz0 . C. the total number of bonding electron pairs in BF3 is 3. D. All of these ____4. What is t ...
... ____3. Which of the following statement is(are) correct? A. the maximum number of electrons possible for a set of p-orbitals is 6? B. the ground state electron configuration of carbon 1s2 2s2 2px1 2py1 2pz0 . C. the total number of bonding electron pairs in BF3 is 3. D. All of these ____4. What is t ...
Carbonyl Condensation Reactions
... A directed aldol reaction is a variation of the crossed aldol reaction that clearly defines which carbonyl compound becomes the nucleophilic enolate and which reacts at the electrophilic carbonyl carbon. The strategy of a directed aldol reaction is as follows: [1] Prepare the enolate of one carbonyl ...
... A directed aldol reaction is a variation of the crossed aldol reaction that clearly defines which carbonyl compound becomes the nucleophilic enolate and which reacts at the electrophilic carbonyl carbon. The strategy of a directed aldol reaction is as follows: [1] Prepare the enolate of one carbonyl ...
Elimination Reactions
... • E1 reactions occur under essentially neutral conditions with polar solvents, such as water, ethyl alcohol or acetic acid. • E1 reactions can also occur with strong bases, but only at low concentration, about 0.01 to 0.1 M or below. • E2 reactions require strong base in high concentration, about 1 ...
... • E1 reactions occur under essentially neutral conditions with polar solvents, such as water, ethyl alcohol or acetic acid. • E1 reactions can also occur with strong bases, but only at low concentration, about 0.01 to 0.1 M or below. • E2 reactions require strong base in high concentration, about 1 ...
haloalkanes and arenes
... Therefore, sulphuric acid is not used during the reaction of alcohols with KI. Instead, a nonoxidizing acid such as H3PO4 is used. ...
... Therefore, sulphuric acid is not used during the reaction of alcohols with KI. Instead, a nonoxidizing acid such as H3PO4 is used. ...
Aldehydes and Ketones
... Aldehydes or ketones with an -hydrogen exist as an equilibrium mixture of keto (H– C–C=O) and enol (C=C–OH) tautomers. The keto form usually predominates. An -hydrogen is weakly acidic and can be removed by a base to produce a resonancestabilized enolate anion. Deuterium exchange of -hydrogens ...
... Aldehydes or ketones with an -hydrogen exist as an equilibrium mixture of keto (H– C–C=O) and enol (C=C–OH) tautomers. The keto form usually predominates. An -hydrogen is weakly acidic and can be removed by a base to produce a resonancestabilized enolate anion. Deuterium exchange of -hydrogens ...
vysoké učení technické v brně
... insertions into C-H bonds, skeletal rearrangements, and additions to double bonds. Carbenes can be classified as nucleophilic, electrophilic, or ambiphilic. Reactivity is especially strongly influenced by type of substituents. For example, if a substituent is able to donate a pair of electrons, most ...
... insertions into C-H bonds, skeletal rearrangements, and additions to double bonds. Carbenes can be classified as nucleophilic, electrophilic, or ambiphilic. Reactivity is especially strongly influenced by type of substituents. For example, if a substituent is able to donate a pair of electrons, most ...
synthetic.applicatio..
... Such ring opening does not affect the C-2 stereochemistry of the aziridine which is maintained in the product α-amino acid derivative. Transfer hydrogenation has been used to open unactivated or sulfonyl activated phenyl aziridine carboxylates8−12 and phenyl aziridine cyanides.13 It is noteworthy an ...
... Such ring opening does not affect the C-2 stereochemistry of the aziridine which is maintained in the product α-amino acid derivative. Transfer hydrogenation has been used to open unactivated or sulfonyl activated phenyl aziridine carboxylates8−12 and phenyl aziridine cyanides.13 It is noteworthy an ...
Wolff rearrangement
The Wolff rearrangement is a reaction in organic chemistry in which an α-diazocarbonyl compound is converted into a ketene by loss of dinitrogen with accompanying 1,2-rearrangement. The Wolff rearrangement yields a ketene as an intermediate product, which can undergo nucleophilic attack with weakly acidic nucleophiles such as water, alcohols, and amines, to generate carboxylic acid derivatives or undergo [2+2] cycloaddition reactions to form four-membered rings. The mechanism of the Wolff rearrangement has been the subject of debate since its first use. No single mechanism sufficiently describes the reaction, and there are often competing concerted and carbene-mediated pathways; for simplicity, only the textbook, concerted mechanism is shown below. The reaction was discovered by Ludwig Wolff in 1902. The Wolff rearrangement has great synthetic utility due to the accessibility of α-diazocarbonyl compounds, variety of reactions from the ketene intermediate, and stereochemical retention of the migrating group. However, the Wolff rearrangement has limitations due to the highly reactive nature of α-diazocarbonyl compounds, which can undergo a variety of competing reactions.The Wolff rearrangement can be induced via thermolysis, photolysis, or transition metal catalysis. In this last case, the reaction is sensitive to the transition metal; silver (I) oxide or other Ag(I) catalysts work well and are generally used. The Wolff rearrangement has been used in many total syntheses; the most common use is trapping the ketene intermediate with nucleophiles to form carboxylic acid derivatives. The Arndt-Eistert homologation is a specific example of this use, wherein a carboxylic acid may be elongated by a methylene unit. Another common use is in ring-contraction methods; if the α-diazo ketone is cyclic, the Wolff rearrangement results in a ring-contracted product. The Wolff rearrangement works well in generating ring-strained systems, where other reactions may fail.