CHE 3332: Organic Chemistry 2 - Week 1 Resource Hello organic chemistry II students! I’m Shubhneet Warar–the Master Tutor for CHE 3332 this semester; I’m also a senior biochemistry major on the pre-med track. You made it through organic chemistry I, so let’s keep building on what you learned and get through this course together! I’ll be making a resource every week summarizing what the two sections of CHE 3332 cover. Virtual group tutoring for this class will be every Wednesday from 5:30-6:30 pm and you can reserve your spot by making an appointment at baylor.edu/tutoring. The two sections of CHE 3332 are currently going at different paces, so this resource will cover two chapters to include material for both sections. Ch 13: Alcohols – review by watching these videos http://leah4sci.com/organic-chemistry-basics/alcohol-reactions-in-organic-chemistry/ [1]

Ch 14: Ethers, Epoxides, Sulfides Reactions of Ethers

1. Williamson Ether Synthesis – start with an alcohol

2. Alkoxymercuration demercuration – start with an alkene

3. Alcohol dehydration – only works for symmetrical ethers

4. Cleave ether with HBr or HI – if you have an unsymmetric ether with alkyl and

aryl groups, it will cleave at the alkyl-oxygen bond

Reactions of Sulfides

1. Sulfur version of Williamson Ether Synthesis

2. Sulfide to sulfoxide to sulfone

Note: Sulfide = thioether Sulfides are analogous to ethers

Sulfide: R – S – R Ether: R – O – R

Preparing Epoxides (3 membered rings with oxygen) 1. From alkene + peracid (mCPBA or MMPP) – adds “syn”

2. Base promoted cyclization of halohydrin

3. Sharpless asymmetric epoxidation (SAE) – makes one enantiomer, not a racemate

Ring Opening Reactions of Epoxides

1. Acid catalyzed – nucleophile prefers to attack tertiary carbon, but will attack primary over secondary carbon

2. Base catalyzed – nucleophile attacks at less substituted carbon of epoxy

Names of ether rings: • Oxirane (epoxide) = 3 membered • Oxetane = 4 membered • Oxolane (furan) = 5 membered • Oxane (pyran) = 6 membered • Dioxane = 6 membered with two

oxygens at opposite sides

Ch 15: IR & Mass Spectrometry

Common IR Functional Groups to Know Structure Wavenumber (cm-1) Shape NH 3400 One hump NH2 3400 Two humps Alcohol (OH) 3300 Broad, long CH 2900 Long, not too broad Carboxylic Acid (OH) Midpoint around 2800 Shifts right, very broad, ugly CN triple bond 2200 Long, skinny CC triple bond 2100 Long, skinny Carbonyl (CO double bond) 1650-1750 Long, not skinny CC double bond 1600 Short, skinny Benzene 1600-2000 Short bumps throughout

This is a great table to understand and memorize!

[2] Here’s a diagram of an IR spectra and where functional groups are typically located.

Mass Spectrometry Ions break in patterns so we must calculate the new weight of the structure after every break. Keep “breaking” the structure until you’re left with a CH3. Use rounded mass values for every atom. Example: How to draw the mass spectra of pentane? Before any breaks, pentane’s weight is 72 amu. M+ = 72

Because a CH3 group is broken off and its mass is 15 amu, this break is named [M-15]+

The fragmented structure has a weight of 57 amu, so it’s peak will be drawn at 57.

Keep following this pattern for every additional break. Remember not to repeat fragments.

Label the fragments as peaks on a mass spectrum.

References

1. Leah4Science Alcohols/Phenols Videos [YouTube] 2. IR figure courtesy of Dr. Zinke’s past SI, Jasmine