Changing counterion can switch the preference for selective 1,2
... electronic properties of the components involved. However, this inbuilt selectivity is rarely complete, and is often challenging to control. However, catalytic methods for divergent regioselective cycloaddition reactions have begun to emerge. For example, Maruoka has reported the site-divergent Diel ...
... electronic properties of the components involved. However, this inbuilt selectivity is rarely complete, and is often challenging to control. However, catalytic methods for divergent regioselective cycloaddition reactions have begun to emerge. For example, Maruoka has reported the site-divergent Diel ...
New Phenylglycine-Derived Primary Amine Organocatalysts for the
... to the previous reports on diamine 5.[2b] It was originally anticipated by us that introducing sterically more demanding side chains through cyclohexylglycine or tert-leucine (amino alcohols 16–17) would enhance the enantioselectivity even further, a hypothesis obviously invalidated by experiment. C ...
... to the previous reports on diamine 5.[2b] It was originally anticipated by us that introducing sterically more demanding side chains through cyclohexylglycine or tert-leucine (amino alcohols 16–17) would enhance the enantioselectivity even further, a hypothesis obviously invalidated by experiment. C ...
Alcohols (R-OH), and alkyl halides, RX
... Step 1: What are the possible monosubstituted products? Step 2: How many hydrogens that yield the same product? (nHi) Step 3: What is the reactivity (Ri) for the hydrogen and halogen type? Step 4: Using the reactivity factors, what are the total possible structures? Step 5: What is the percent of ea ...
... Step 1: What are the possible monosubstituted products? Step 2: How many hydrogens that yield the same product? (nHi) Step 3: What is the reactivity (Ri) for the hydrogen and halogen type? Step 4: Using the reactivity factors, what are the total possible structures? Step 5: What is the percent of ea ...
Ring-Opening Metathesis Polymerization of Norbornene by Cp
... (59) Tlenkopatchev, M. A.; Fomine, S.; Fomina, L.; Gavino, R.; Ogawa, T. Mex. Polym. J. 1997, 29, 622-625. ...
... (59) Tlenkopatchev, M. A.; Fomine, S.; Fomina, L.; Gavino, R.; Ogawa, T. Mex. Polym. J. 1997, 29, 622-625. ...
ChemConnections
... same types of atoms in the same physical state, the more atoms per molecule, the more types of motion available to it and, thus, the higher its entropy. (d) 4 mol S2. The two samples contain the same number of sulfur atoms, but different numbers of molecules. Despite the greater complexity of S8 , t ...
... same types of atoms in the same physical state, the more atoms per molecule, the more types of motion available to it and, thus, the higher its entropy. (d) 4 mol S2. The two samples contain the same number of sulfur atoms, but different numbers of molecules. Despite the greater complexity of S8 , t ...
Cracking (chemistry)
In petroleum geology and chemistry, cracking is the process whereby complex organic molecules such as kerogens or heavy hydrocarbons are broken down into simpler molecules such as light hydrocarbons, by the breaking of carbon-carbon bonds in the precursors. The rate of cracking and the end products are strongly dependent on the temperature and presence of catalysts. Cracking is the breakdown of a large alkane into smaller, more useful alkanes and alkenes. Simply put, hydrocarbon cracking is the process of breaking a long-chain of hydrocarbons into short ones. More loosely, outside the field of petroleum chemistry, the term ""cracking"" is used to describe any type of splitting of molecules under the influence of heat, catalysts and solvents, such as in processes of destructive distillation or pyrolysis. Fluid catalytic cracking produces a high yield of petrol and LPG, while hydrocracking is a major source of jet fuel, Diesel fuel, naphtha, and again yields LPG.