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Saoist
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looked in books/googled for info about this...i know what it IS, but don't understand why it happens. anyone?
Markownikoff's Rule, also known as the Markownikoff's Principle or the Markownikoff's law, is a rule in organic chemistry that states that during the addition of a protic acid (H-X) to an asymmetric alkene, the hydrogen atom will add to the carbon atom that already has the greater number of hydrogen atoms bonded to it.
Markownikoff's Rule is important because it helps predict the major product in an addition reaction of an asymmetric alkene. It also helps understand the mechanism of the reaction and aids in the synthesis of desired products.
Markownikoff's Rule works based on the stability of the intermediate carbocation formed during the addition reaction. The more substituted the carbocation is, the more stable it is and thus, the preferred product is the one that leads to the more substituted carbocation.
Markownikoff's Rule was proposed by Russian chemist Vladimir Markownikoff in 1870, based on his observations on the addition of hydrogen halides to unsymmetrical alkenes. It was later confirmed and explained by other scientists through further experiments and theoretical studies.
Yes, there are some exceptions to Markownikoff's Rule, especially in cases where steric hindrance or electronic effects play a significant role. Some examples include reactions involving bulky reagents, cyclic alkenes, and conjugated systems. In these cases, the rule may be overridden by other factors and the minor product may be formed as the major product instead.