New User Special Price Expires in

Let's log you in.

Sign in with Facebook


Don't have a StudySoup account? Create one here!


Create a StudySoup account

Be part of our community, it's free to join!

Sign up with Facebook


Create your account
By creating an account you agree to StudySoup's terms and conditions and privacy policy

Already have a StudySoup account? Login here

CHEM 2222 Chapter 23 Notes

by: annafen

CHEM 2222 Chapter 23 Notes Chem 212 - Organic Chemistry II

GPA 3.56

Preview These Notes for FREE

Get a free preview of these Notes, just enter your email below.

Unlock Preview
Unlock Preview

Preview these materials now for free

Why put in your email? Get access to more of this material and other relevant free materials for your school

View Preview

About this Document

Organic Chemistry (Carey) Chapter 23
Organic Chemistry II
Dr. Alissa Hare
Class Notes
Carbohydrates, Organic Chemistry
25 ?




Popular in Organic Chemistry II

Popular in Chemistry

This 34 page Class Notes was uploaded by annafen on Sunday May 29, 2016. The Class Notes belongs to Chem 212 - Organic Chemistry II at Vanderbilt University taught by Dr. Alissa Hare in Spring 2016. Since its upload, it has received 5 views. For similar materials see Organic Chemistry II in Chemistry at Vanderbilt University.


Reviews for CHEM 2222 Chapter 23 Notes


Report this Material


What is Karma?


Karma is the currency of StudySoup.

You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!

Date Created: 05/29/16
23.1 Classification of Carbohydrates Carbohydrates • Carbohydrates were considered to be “hydrates of carbon” because their molecular formulas correspond to C n(H2O) m • A carbohydrate is a polyhydroxy aldehyde or polyhydroxy ketone • Carbohydrates have several things to consider - 1. Number of Monomers • • • • 1 Carbohydrates 2. Position of carbonyl group • • 3. Number of carbons • • • 4. Cyclic form 2 23.2 Fischer Projections and D, L Notation Fischer Projections and D, L Notation • Fischer projections are the two crossed lines that represent a tetrahedral carbon • To assign R or S, with the H pointing toward you, solve the configuration and assign the opposite 3 Allowed Manipulations • Fischer projections can be rotate by 180º in the plane of the page • If one group is held steady, the other 3 groups can be rotated clockwise or counterclockwise 4 Fischer Projections 1. Assign priorities to the four substitutents according to the Cahn-Ingold- Prelog rules 2. Perform the two allowed manipulations of the Fischer projection to place the lowest priority group at thetop or bottom 3. If the priority of the other groups 1→2→3 is clockwise then assign the carbon as R, if priority of the other groups 1→2→3 is counterclockwise then assign the center as S. • However, if the lowest priority group is pointing forward, you can assign the wrong stereochemistry and thenswitch it 5 Fischer Projections and D, L Notation • Remember for most molecules, we can’t correlate absolute configuration with D or L = (+) or (-) • Fischer arbitrarily assigned (+)-glyceralderhyde to be D and (-)- glyceraldehyde to be L • D-carbohydrates 6 Fischer Projections and D, L Notation • Carbohydrates are designated as D- or L- according to the stereochemistry of the highest numbered chiral carbon of the Fischer projection. • If the hydroxyl group of the highest numbered chiral carbon is pointing to the right, the sugar is designated asD (Dextro : Latin for on the right side). • If the hydroxyl group is pointing to the left, the sugar is designated asL (Levo : Latin for on the left side). 7 23.3 The Aldotetroses The Aldotetroses • Glyceraldehyde is the smallest carbohydrate – it is an aldotriose and has 3 carbons • The four stereoisomers of 2,3,4-trihydroxybutanal are the aldotetroses 8 23.4 Aldopentoses and Aldohexoses The Aldopentoses 3 • Aldopentoses have three chirality centers and therefore 2 = eight stereoisomers • The 4 L-aldopentoses have the same name as their enantiomer except the prefix is L- rather than D- 9 The Aldohexoses • In aldohexoses there are four chirality centers and therefore 2 = sixteen stereoisomers • Eight D-aldohexoses and eight L-aldohexoses 10 23.5 A Mnemonic for Carbohydrate Configurations Remembering the Aldohexoses • Provided the 8 D-aldohexoses are drawn in the correct order then the mnemonic is: “All altruists gladly make gum in gallon tanks.” • The words of the sentence stand for: allose, altrose, glucose, mannose, gulose, idose, galactose, talose. 11 23.6 Cyclic Forms of Carbohydrates Furanoses • Aldoses contain an aldehyde and alcohols which react to form cyclic hemiacetals • Five-membered cyclic hemiacetals are furanose forms • Six-membered cyclic hemiacetals are pyranose forms 12 Furanoses • Cyclization of carbohydrates to the hemiacetal creates a new chiral center • The hemiacetal or hemiketal carbon of the cyclic form of carbohydrates is the anomeric carbon • Carbohydrate isomers that differ only in the stereochemistry of the anomeric carbon are called anomers 13 From Fischer Projection to Haworth • Substituents that are right in a Fischer projection are “down” in the Haworth structure; those to the left are “up.” 14 Haworth Formulas and α and β 1. For carbohydrates of the D series, the configuration of the anomeric carbon is α if its OH is down, β if the OH at the anomeric carbon is up 3. For carbohydrates of the L series, the configuration of the anomeric carbon is α if its OH is up, β if the OH at the anomeric carbon is down 15 23.7 Cyclic Forms of Carbohydrates: Pyranose Forms Pyranose Formation From D-Ribose • Draw the eclipsed conformation and then the α- and β-pyranose forms 16 Pyranose-Furanose-Open Chain • Six-membered rings more stable so more abundant – exist in the chair conformation • Small amounts of open chain form and can also form the furanose 17 23.8 Mutarotation Mutarotation • The α- and β- anomers are in equilibrium and can interconvert through the open form • While anomers can be separated, if allowed to react with water, the anomer will undergo mutarotation and a mixture will form 18 23.9 Carbohydrate Conformation: The Anomeric Effect The Anomeric Effect • The anomeric effect stabilizes an electronegative substituent on the anomeric carbon by orbital mixing • The axial substituent is stabilized by interaction of a non-bonding electron pair on the ring O with the σ* orbital which lowers the energy • The electronegative group prefers to be axial 19 23.10 Ketoses Ketoses • Ketoses are less common than aldoses • Carbonyl is normally on C-2 20 Ketoses and Cylclic Hemiketals • Ketoses exist mainly as cyclic hemiketals • The anomeric carbon of a furanose or pyranose form of a ketose bears both a hydroxyl group and a CH 2OH group 21 23.11 Deoxy Sugars Deoxy Sugars • In deoxy sugars, a hydroxyl group is replaced by hydrogen 22 23.14 Glycosides: The Fischer Glycosidation Glycosides • Glycoside formation is related to acetal formation • The anomeric hydroxyl group is replaced by some other substituent • In Fischer glycosidation carbohydrates react with an alcohol in the presence of an acid catalyst • The reaction is thermodynamically controlled 23 Mechanism of the Fischer Glycosidation 24 23.15 Disaccharides Disaccharides • Disaccharides are comprised of two monomers connected at the anomeric position • The -OR group of the glycoside is a second sugar molecule 25 23.16 Polysaccharides Polysaccharides • Cellulose: glucose polymer made up of • Amylose: glucose polymer made up of 26 23.17 Application of Familiar Reactions to Monosaccharides Reactions 27 Reactions 28 Reactions 29 23.18 Oxidation of Monosaccharides Oxidation • C1 of aldoses can be selectively oxidized to the carboxylic acid (aldonic acids) with Br 2or Ag(I) (Tollen’s test) • Most commonly used method for preparing aldonic acids is by oxidation with bromine in aqueous solution or nitric acid 30 Oxidation of Monosaccharides • Oxidation of aldoses to aldaric acids with HNO 3 • Uronic Acids are carbohydrates in which only the terminal -CH OH is 2 oxidized to a carboxylic acid • Oxidative cleavage of vicinal diol functions in carbohydrates uses periodic acid (HIO 4) or sodium metaperiodate (NaIO ). 4 31 23.19 Glycosides: Synthesis of Oligosaccharides Synthesis of Oligosaccharides • Fischer glycosidation is thermodynamically controlled and favors the formation of pyranose over furanose • The anomeric effect causes the α stereoisomer to predominate over the β 32 Synthesis of Oligosaccharides General strategy: 1. Prepare a suitably protected glycosyl donor and a glycosyl acceptor. The glycosyl donor has a leaving group at the anomeric carbon. The glycosyl acceptor contains one nucleophilic OH. All the other hydroxyl groups are protected 2. Formation of the glycosidic C ⎯ O bond by a nucleophilic substitution 3. Removal of all protecting groups 33 Mechanism of Glycosidation 34


Buy Material

Are you sure you want to buy this material for

25 Karma

Buy Material

BOOM! Enjoy Your Free Notes!

We've added these Notes to your profile, click here to view them now.


You're already Subscribed!

Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'

Why people love StudySoup

Jim McGreen Ohio University

"Knowing I can count on the Elite Notetaker in my class allows me to focus on what the professor is saying instead of just scribbling notes the whole time and falling behind."

Anthony Lee UC Santa Barbara

"I bought an awesome study guide, which helped me get an A in my Math 34B class this quarter!"

Jim McGreen Ohio University

"Knowing I can count on the Elite Notetaker in my class allows me to focus on what the professor is saying instead of just scribbling notes the whole time and falling behind."

Parker Thompson 500 Startups

"It's a great way for students to improve their educational experience and it seemed like a product that everybody wants, so all the people participating are winning."

Become an Elite Notetaker and start selling your notes online!

Refund Policy


All subscriptions to StudySoup are paid in full at the time of subscribing. To change your credit card information or to cancel your subscription, go to "Edit Settings". All credit card information will be available there. If you should decide to cancel your subscription, it will continue to be valid until the next payment period, as all payments for the current period were made in advance. For special circumstances, please email


StudySoup has more than 1 million course-specific study resources to help students study smarter. If you’re having trouble finding what you’re looking for, our customer support team can help you find what you need! Feel free to contact them here:

Recurring Subscriptions: If you have canceled your recurring subscription on the day of renewal and have not downloaded any documents, you may request a refund by submitting an email to

Satisfaction Guarantee: If you’re not satisfied with your subscription, you can contact us for further help. Contact must be made within 3 business days of your subscription purchase and your refund request will be subject for review.

Please Note: Refunds can never be provided more than 30 days after the initial purchase date regardless of your activity on the site.