Search results
Results from the WOW.Com Content Network
Such reactions are said to be anti-Markovnikov, since the halogen adds to the less substituted carbon, the opposite of a Markovnikov reaction. The anti-Markovnikov rule can be illustrated using the addition of hydrogen bromide to isobutylene in the presence of benzoyl peroxide or hydrogen peroxide. The reaction of HBr with substituted alkenes ...
In 1869, a Russian chemist named Vladimir Markovnikov demonstrated that the addition of HBr to alkenes usually but not always resulted in a specific orientation. Markovnikov's rule, which stems from these observations, states that in the addition of HBr or another hydrogen halide to an alkene, the acidic proton will add to the less substituted carbon of the double bond. [3]
The reaction follows Markovnikov's rule (the hydroxy group will always be added to the more substituted carbon). The oxymercuration part of the reaction involves anti addition of OH group but the demercuration part of the reaction involves free radical mechanism and is not stereospecific, i.e. H and OH may be syn or anti to each other.
Markovnikov's rule predicts that the hydrogen atom is added to the carbon of the alkene functional group which has the greater number of hydrogen atoms (fewer alkyl substituents). Zaitsev's rule predicts that the major reaction product is the alkene with the more highly substituted (more stable) double bond.
Ever since the first wave of boba tea shops hit the U.S. in the 1990s, the popularity of the Taiwanese drink with floating tapioca balls sipped through oversized straws has been bursting ...
Vladimir Markovnikov was born on December 22, 1837, in Chernorechye near Nizhny Novgorod, Russian Empire (now Dzerzhinsk, Nizhny Novgorod Oblast, Russian Federation). Soon after his birth, his father retired and settled in a family estate received as a dowry from his wife's family at marriage, in the village of Ivanovo, Knyagininsky district of the Nizhny Novgorod province, where Markovnikov ...
In the first step, the alkene acts as a nucleophile and attacks the proton, following Markovnikov's rule. In the second step an H 2 O molecule bonds to the other, more highly substituted carbon. The oxygen atom at this point has three bonds and carries a positive charge (i.e., the molecule is an oxonium ).
Zaytsev submitted his Dr. Chem. dissertation in 1870, and was awarded the degree over the indirect objections of Markovnikov (as second examiner of the dissertation, Markovnikov had written an overtly positive assessment that was meant to be read between the lines). The same year, he was promoted to Ordinary Professor of Chemistry.