Chapter 11.7, Problem 11.69P

Interpretation Introduction

Interpretation:

The product has to be predicted for the given reaction.

Concept Introduction:

Addition reactions are the one in which the groups are added to an unsaturated double bond.  The double bond is destroyed because the groups are added across the double bond.  If the considered alkene is a symmetrical one, then there is no difference in the product obtained but if the alkene is an unsymmetrical one, then regiochemistry decides the products that are obtained.

When two similar groups are added across a double bond, regiochemistry is irrelevant.  When adding two different groups across the double bond of an unsymmetrical alkene, the regiochemistry becomes relevant.  In simple words, it can be said that, when two different groups are added across a double bond, then regiochemistry becomes relevant.

Markovnikov Addition

    In the vinylic bond, if the bulky group gets substituted in the carbon atom that is more substituted means, it is known as Markovnikov’s addition.

anti-Markovnikov Addition

    In the vinylic bond, if the bulky group gets substituted in the carbon atom that is less substituted means, it is known as anti-Markovnikov’s addition.

Stereochemistry can also be determined for the product obtained by the way of addition of groups that adds across the double bond.  If the two groups add in the same side of the plane means it is known as syn addition and if the two groups add in the opposite side of the plane means it is known as anti addition.  This can be done by considering the given alkene in a planar form by using wedge and dash bonds.

In case of ring system, namely cycloalkenes, the products obtained are very easy to draw because there is no need to rotate and redraw the alkene.