M2 Lesson 3 - Isomerism: Fischer Structure and Haworth Structure

Structural or constitutional isomers

share the same chemical formulas, but their atoms are arranged differently.

Skeletal isomerism (chain isomerism)

structural isomers in which components of the skeleton are arranged in a different order. This is most commonly seen when the skeleton or backbone consists of a carbon chain

Position isomerism (regioisomerism)

constitutional isomers in which a functional group or substituent changes position on a parent structure.

Functional group isomerism

structural isomers with the same molecular formula, but with atoms connected differently so dissimilar functional groups are formed.

chirality centers

All carbohydrates have 1 or more

D

is used when the –OH group is drawn on the right side of the carbon chain

L

is used when the –OH group is drawn on the left side of the carbon chain

glucose

as four chirality centers and is drawn as

farthest

The configuration of the chirality center _____ from the carbonyl group determines whether a monosaccharide is D or L.

D-sugars

All naturally occurring sugars are

hemiacetal

When an aldehyde reacts with an alcohol, a ______ is formed

anomer

The C atom that is part of the hemiacetal is a new chirality center, called the _____ carbon.

90degree

The first step in cyclization is to rotate glucose

six-membered ring

after turning to 90 degrees next, the chain must be twisted around, forming
a ______-

Haworth projections

As the reaction occurs, there are two cyclic forms of D-glucose, an a anomer and a b anomer.
•These rings are called _________.