MendelSet works best with JavaScript enabled. Please enable JavaScript.
If you are using NoScript or another JavaScript blocker, please add MendelSet.com to your whitelist.
Textbook and Chapter: Carey and Giuliano 8th Ed. (2010), Chapter 7
Keywords: chiral resolution, Fischer projections, R and S configuration, stereochemistry
Description: This mendel set covers various stereochemistry topics, such as:
Total Problems: 8
Textbook and Chapters: Carey and Giuliano 8th Ed. (2010), Chapters 4, 5, 6
Keywords: carbocation, carbocation formation, carbocation rearrangement
Description: This mendel set guides you through everything you have to know about carbocations:
Also includes some practice problems: addition to an alkene, dehydration (E1), and substitution (SN1).
Keywords: alkene addition, carbocation
Description: Identify the intermediates (carbocation, radical, borane intermediate, etc.) and products for important reactions dealing with alkenes. Good review for an orgo1 midterm.
Total Problems: 7
Textbook and Chapter: Carey and Giuliano 8th Ed. (2010), Chapter 1
Keywords: formal charge, Lewis structures, resonance
Description: This mendel set goes through the basics of structure:
Keyword: acid strength
Description: This mendel set goes through rules that affect acid and base strength:
"What makes a compound stable?" problems are key to understand for the MCAT.
Total Problems: 6
Textbook and Chapter: Carey and Giuliano 8th Ed. (2010), Chapter 3
Keywords: conformational analysis, cyclohexane chair forms
Description: Reviews cyclohexane chair forms and conformations of butane:
Total Problems: 4
Textbook and Chapters: Carey and Giuliano 8th Ed. (2010), Chapters 4, 5
Keywords: carbocation rearrangement, free radical halogenation, mechanism
Description: Practice mechanisms from the first half of Fall semester orgo. Dehydration (E1), substitution with carbocation rearrangement (SN1), and free-radical bromination.
Total Problems: 3
Propose a synthesis to accomplish each transformation. The only carbon sources allowed are alkenes and NaCN.
a) The starting alkene has 4 carbons, and the product has 5 carbons and a nitrogen. So you have to add 1C and 1N. This screams "add cyanide!"
Based on the location of the alcohol on the product, it looks like the way to go is to add NaCN to an epoxide. This puts the -CN and the -OH in the right positions.
b) The best way to prepare 2º and 3º amines is via reductive amination. Working backwards, the product can be prepared from a 4-carbon aldehyde (butyraldehyde) and a 3-carbon amine (propyl amine).
Performing hydroboration on the butene results in the anti-Markovnikov alcohol, which can be oxidized to the aldehyde using PCC.
To prepare propyl amine from an alkene, add HBr/peroxides to make the bromide (anti-Markovnikov), and then add NaN3 follow by H2/Pd.
For each amine below, show all Hofmann elmination products.
If more than one product is formed, predict which one will be the major product.
The Hoffman elimination first turns an amine into a better leaving group by methylating it with excess methly iodide, and then eliminates the methylated amine using base (such as -OH fomed from Ag2O in H2O). The products are alkenes.
This reaction is similar to an E2 elimination in that a beta proton is ripped off, and the alkene forms between alpha and beta. One notable difference from the E2 is that the less substituted product is favored, so Hoffman products are usually anti-Zaitsev.
a) There are three different types of beta protons, so three possible products can form. Product A is the least substituted alkene, so it's the major product.
b) There is only one possible product. The Hoffman elimination can't be done on aryl hydrogens (benzene rings).
The nitrosyl cation is shown below. Also shown are several proposed resonance arrows, only one of which is correct.
Draw the resonance forms that would follow from each set of arrows, and include formal charges. Which one is the correct resonance form? Explain your reasoning.
When evaluating possible Lewis structures the most important rule to follow is the octet rule: every atom must be surrounded by 8 and only 8 electrons (atoms in period 3 or below on the periodic table have d orbitals and so can contain more than 8 electrons, but that exception does not apply here).
Do any of the resonance forms drawn have atoms that break the octet rule? Yes- they all do! Except for resonance arrows in D. So D is the correct resonance form.
