Chapter 7, Problem 92IP

(a)

Interpretation Introduction

Interpretation:

The trisubstituted pi bond and its configuration have to be identified and given.

Concept Introduction:

Z-isomer: when two groups with higher priorities are on same side of alkene double bond, then it is called as Z-isomer. Priority depends on atomic number of atoms. Greater the atomic number, higher the priority.

E-isomer: when two groups with higher priorities are on opposite side of alkene double bond, then it is called as E-isomer. Priority depends on atomic number of atoms.  Greater the atomic number, higher the priority.

(b)

Interpretation Introduction

Interpretation:

The total number of possible stereoisomers for pladienolide B has to be described.

Concept Introduction:

Stereo isomers: These are isomers, which are having same molecular formula but differ in their spatial arrangement. The number of stereoisomers in a compound with n number of stereocenters are ${\text{2}}^{\text{n}}$.

(c)

Interpretation Introduction

Interpretation:

The enantiomer of pladienolide B has to be drawn.

Concept Introduction:

Enantiomers: These isomers are non-superimposable mirror images.  Enantiomers have same physical and chemical properties, but their ability to rotate plane-polarized light (+/-) by equal amounts are in opposite directions.

(d)

Interpretation Introduction

Interpretation:

The diastereomer identical to pladienolide B except for chiral center connected to ester oxygen has to be drawn.

Concept Introduction:

Diastereomers: These isomers are non-superimposable and not mirror images.  It occurs when stereoisomers of a compound have different configuration at stereocenters and are non-mirror image.

(e)

Interpretation Introduction

Interpretation:

The diastereomer identical to pladienolide B except for configuration of disubstituted pi bond outside the ring has to be drawn.

Concept Introduction:

Diastereomers: These isomers are non-superimposable and not mirror images.  It occurs when stereoisomers of a compound have different configuration at stereocenters and are non-mirror image.