CHEMICAL REACTIVITY AND MECHANISMS, AND SUBSTITUTION REACTIONS 1.
... steric effect; larger groups interfere with the approaching nucleophile). SN1 reactions are faster for 3° substrates (because the more stable the carbocation, the faster the reaction; this means 3° > 2° >> 1° > CH3). Vinylic (R2C=CR-) and aromatic substrates are unreactive in either reaction type. A ...
... steric effect; larger groups interfere with the approaching nucleophile). SN1 reactions are faster for 3° substrates (because the more stable the carbocation, the faster the reaction; this means 3° > 2° >> 1° > CH3). Vinylic (R2C=CR-) and aromatic substrates are unreactive in either reaction type. A ...
Coordination Chemistry Reviews 272 - Didier Astruc`s Library
... six-membered cycles are usually formed. Besides, bridging coordination modes with two metals coordinating to two of the nitrogen atoms are possible (types D and E). The second mode is C5 coordination with deprotonated triazoliums to form N-heterocyclic carbenes (NHCs, Fig. 3). NHCs are a class of we ...
... six-membered cycles are usually formed. Besides, bridging coordination modes with two metals coordinating to two of the nitrogen atoms are possible (types D and E). The second mode is C5 coordination with deprotonated triazoliums to form N-heterocyclic carbenes (NHCs, Fig. 3). NHCs are a class of we ...
Catalytic, Enantioselective Alkylations of N,O- and
... acetophenone developed. In addition, the alcohol proton disappeared, indicating Osilylation (Scheme 1). A second equiv of enol silane 4a was then added to the mixture and the reaction was monitored; no product formation was noted even after extended periods of time. After addition of the catalyst 2 ...
... acetophenone developed. In addition, the alcohol proton disappeared, indicating Osilylation (Scheme 1). A second equiv of enol silane 4a was then added to the mixture and the reaction was monitored; no product formation was noted even after extended periods of time. After addition of the catalyst 2 ...
Metal-Catalyzed Epoxidations of Alkenes with Hydrogen
... such reactions conditions, resulting in low yields.62 This is common for systems with Lewis-acidic catalysts that use aqueous H2O2 at high temperatures. Due to the above limitations, such tungsten catalysts may only be used to produce relatively stable epoxides, particularly terminal aliphatic ones, ...
... such reactions conditions, resulting in low yields.62 This is common for systems with Lewis-acidic catalysts that use aqueous H2O2 at high temperatures. Due to the above limitations, such tungsten catalysts may only be used to produce relatively stable epoxides, particularly terminal aliphatic ones, ...
Microsoft Word
... efficacy of the sulfoxide group in the stereoselective auxiliary-induced reactions is mainly due to the steric and stereoelectronic differences between the substituents of the chiral sulfur atom: a lone pair of electrons, an oxygen atom and two different carbon ligands. It is well known that sulfoxi ...
... efficacy of the sulfoxide group in the stereoselective auxiliary-induced reactions is mainly due to the steric and stereoelectronic differences between the substituents of the chiral sulfur atom: a lone pair of electrons, an oxygen atom and two different carbon ligands. It is well known that sulfoxi ...
Chapter 3 Nonchain Reactions - Radical Reactions of Carbohydrates
... causes transformation to take place only once. The radicals that participate in nonchain reactions sometimes are formed by bond homolysis but more often are produced by electron transfer. Bond homolysis is usually a photochemical reaction. Electron transfer typically involves transition-metal-genera ...
... causes transformation to take place only once. The radicals that participate in nonchain reactions sometimes are formed by bond homolysis but more often are produced by electron transfer. Bond homolysis is usually a photochemical reaction. Electron transfer typically involves transition-metal-genera ...
