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Elimination reaction of cyclohexanol to cyclohexene with sulfuric acid and heat [1] An elimination reaction is a type of organic reaction in which two substituents are removed from a molecule in either a one- or two-step mechanism. [2] The one-step mechanism is known as the E2 reaction, and the two-step mechanism is known as the E1 reaction ...
The stereoelectronic effect, which is the interaction shown above when the acceptor orbital is the σ*(Si–CH 3), appears to be a more predominant factor in determining the reaction selectivity against the steric hindrance and even wins over the penalty of the disrupted conjugation system of the product due to steric clash.
Factors that affect the rate determining step are stereochemistry, leaving groups, and base strength. A theory, for an E2 reaction, by Joseph Bunnett suggests the lowest pass through the energy barrier between reactants and products is gained by an adjustment between the degrees of C β-H and C α-X rupture at the
Stereochemistry, a subdiscipline of chemistry, studies the spatial arrangement of atoms that form the structure of molecules and their manipulation. [1] The study of stereochemistry focuses on the relationships between stereoisomers, which are defined as having the same molecular formula and sequence of bonded atoms (constitution) but differing in the geometric positioning of the atoms in space.
More generally, Zaytsev's rule predicts that in an elimination reaction the most substituted product will be the most stable, and therefore the most favored. The rule makes no generalizations about the stereochemistry of the newly formed alkene, but only the regiochemistry of the elimination reaction. While effective at predicting the favored ...
Diels–Alder reactions were used in the original synthesis of prostaglandins F2α and E2. [76] The Diels–Alder reaction establishes the relative stereochemistry of three contiguous stereocenters on the prostaglandin cyclopentane core. Activation by Lewis acidic cupric tetrafluoroborate was required.
Stereoconvergence can be considered an opposite of stereospecificity, when the reaction of two different stereoisomers yield a single product stereoisomer. The quality of stereoselectivity is concerned solely with the products, and their stereochemistry. Of a number of possible stereoisomeric products, the reaction selects one or two to be formed.
In the latter sense, the term stereospecific reaction is commonly misused to mean highly stereoselective reaction. Chiral synthesis is built on a combination of stereospecific transformations (for the interconversion of existing stereocenters) and stereoselective ones (for the creation of new stereocenters), where also the optical activity of a ...