Question

FN PRINS Testbank, Question 062 What is the expected major product for the following reaction? 1. Hg(OAc)2, H20 2. NaBH, NaOH HO + enantiomer + enantiomer enantiomer + enantiomer + enantiomer OOOOO

Answer 1

.. e , 1.) Hg (0AC)2, 160 2) MB Hy, waone bys ?? action is basically an example of oxymeneuration oluration reaction, a well known method of water reaction by an even 'to This reaction is basically an es -demerturation reacho addition to alkene system. attack. In the frist step, the nucleophilic double bond is the mercury ion, el ejeeling an acetony group. The fron Pair on the mercury ion in turn attacks a Carbon the double bond, forming a mercuronium ion in which mercury atom bears a positive change. The electrons in highest occur pied molecular orbital ( Homol of the de double bond are donated to mercury's empty 65 orbital and electrons in Hgs ang orbital are donated in the dowest unoccupied molecular orbital of the alkene In Ba 2nd step: the nuclophilic watermolecule attacks more substituted carbon, liberating the elections Participating in it's bond with mecury. The es collapse to the mercury ion and neutralizes it. The only gen in the water molecule bears a positive charge. In, 3rd step, the negatively charged acetony ion that has expelled in the first stel attacks ahydrogen of the water group, forming the waste product HOAG. The two electrons participating in the bond between anygen- and the attacked hydrogen collapseinto anygen and creating the final product an alcohol. ? In practice, the mercury adduct Product created by the a rt mymer curation for reaction is almost always treated win ABHg called demersuratom, when, acetonit ina stero is repren replaced by a hydrogen Chemically ensitive reaction, known as reductiver elimination. Atsto' Hg-OAL? gr, is re pn sens tive no a Scanned with Cam Seammer

- Reaction mechanism sequentes; a one R-CHEC R-Ct-ch/ Alo-Hi-one - 7 öll 449-01 Ch 4:49-040 R-ci-cay SAC R-CA menul NaBty du Are vool R-CH - W to reductive i elemination in - bonic mediun ole (more substitueted • alcohol is the major products. As, of we observed oxymercuation-demerturation follows Markovnikon' selectivity rule to give the major product. Markounikourule: In and the addition reactions of unsymm. trical addendums with Usymmetrical alkeneas, the Gine part of the addendum becomes attached with that do ubly bonded Carbon atom which have lessermo. of hydrogen atom. now, in our problem; the alkene is auss un symmetrical as of the addendum sie ho. a so, the Sld will attached with that corrbon which have lessno, of hydrogen with and that carbon which lift will attached have higher no. of Hydrogen according to Marokoni kov nule, theresen k 1.) HOA), ho a k (majon 27 Ma BHey, Noole no hydrogen. As here one center is chiral center, it can be K 150, ophon (IV) is the right answer csscanned with CamScanner 1 product) C e ao represented as
so, here major product is option IV... And the reaction is oxymercuration-demercuration.

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