Vladimir Markovnikov
Markovnikov began his career at University where he rose to rank of professor at University of Odessa. He was the one that postulated Markovnikov's rule, which stated that in addition to polar reagent to unsymmetrical alkene the positive part of the polar reagent is attached to the carbon having the highest number of hydrogen while the negative part of the polar reagent is attached to the carbon having the lowest number of hydrogen. Markovnikov also contributed to organic chemistry by finding carbon rings with more than six carbon atoms, a ring with four carbon atoms.