Chapter 23, Problem 23.60SP

(a)

Interpretation Introduction

Interpretation:

The Fischer structure for the open chain form of tagatose is to be drawn.

Concept introduction:

An asymmetric carbon atom is represented as a cross in Fisher projection. The carbon chain is kept along the vertical line. The groups attached asymmetric carbon atoms are arranged according to their configuration in Fisher projection. When two groups on a fisher projection are interchanged, the configuration of chiral carbon also changes from (R) to (S) aur (S) to (R).

(b)

Interpretation Introduction

Interpretation:

The most stable conformation of the most stable cyclic hemiacetal form of tagatose is to be drawn.

Concept introduction:

The most stable cyclic conformation is the one in which heavier groups are at the equatorial position and the lighter groups are at the axial position to avoid any steric hindrance.