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Single-Step Reaction
Correct Answer: BTertiary alkyl halides when plopped into protic solvents (like water!) are prone to Sn1 and E1 elimination reactions. Usually Sn1 reactions predominate at lower temperatures, but if...
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Multi-Step Reaction
Correct Answer: DFirst, ethylene glycol reacts with the aldehyde under acidic conditions to yield an acetal, which masks the aldehyde for the Grignard reaction. Step 2 involves reaction of magnesium...
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NMR Spectroscopy
Correct Answer: CThere are only aromatic (6-8 ppm) protons and an aldehydic proton (10 ppm) visible in the spectrum. Furthermore, there are two doublets in the aromatic region suggesting the presence...
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NMR Spectroscopy
Correct Answer: ABenzene has six chemically and magnetically equivalent protons (hydrogens). So you see a singlet that appears in the aromatic (6-8 ppm) region of the 1H NMR spectrum. All the other...
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Multi-Step Reaction
Correct Answer: CDibromination of styrene followed by two sequential E2 eliminations to give the alkyne.
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Stereochemistry
Correct Answer: COnly the two central double bonds (alkenes) have E/Z stereoisomerism. The molecule can either be E/E, E/Z, Z/E, or Z/Z. That is a total of four possible stereoisomers.
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What’s the Relationship?
Correct Answer: IdenticalThese are resonance structures of toluene.
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What’s the Relationship?
Correct Answer: DiastereomersStereoisomers that are not enantiomers are diastereomers. These are molecules with the same chemical formula, same connectivity, but they are not mirror images of each...
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What’s the Relationship?
Correct Answer: CAllenes can have axial chirality, which is when a molecule is chiral but does not possess asymmetric atoms (ie. no chiral centers!). Shown above are non-superimposable allene...
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What’s the Relationship?
Correct Answer: BThese two isomers have different connectivities. Therefore they are constitutional (structural) isomers.
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What’s the Relationship?
Correct Answer: AThese structures represent the SAME molecule. There is an internal mirror plane of symmetry that bisects the molecule. This means that the molecule is meso and therefore achiral.
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What’s the Relationship?
Correct Answer: CThese structures represent NON-SUPERIMPOSABLE MIRROR IMAGES. These molecules lack symmetry and are chiral. They are stereoisomers AND mirror images; therefore, they are enantiomers.
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What’s the major product?
Correct Answer: AThis is the Bayer-Villiger reaction. mCPBA and other peracids will insert an oxygen into a ketone to produce an ester. In the case of unsymmetrical ketones, the oxygen gets inserted...
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How many proton NMR signals would you expect for:
Correct Answer: BThere are four unique protons color coded below.
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What’s the correct structure?
Correct Answer: DThe 5H in the aromatic region suggests a phenyl group (C6H5). Then, the doublet that integrates to 6H and septet that integrates to 1H is highly indicative of an isopropyl group. The...
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NMR Spectroscopy Guide
Nuclear Magnetic Resonance (NMR) Spectroscopy is an invaluable tool used by organic chemists to elucidate the structure of molecules they are working with. When you take organic chemistry, you’ll want...
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Functional Groups that you should memorize for organic chemistry
You should at least memorize these functional groups before starting a class in organic chemistry. Alcohol, ether, ketone, aldehyde, alkene, carboxylic acid, amine, alkyne, epoxide, and diol. Also:...
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Sandmeyer Reactions
Sandmeyer reactions are an incredibly powerful set of transformations that can convert a C-N bond in an aromatic molecule to a variety of carbon-heteroatom, carbon-carbon, and carbon-H bonds. To make...
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Friedel-Crafts Alkylation and Acylation
Friedel-Crafts alkylation and Friedel-Crafts acylation reactions are electrophilic aromatic substitution reactions that form C-C bonds. When you treat benzene with an alkyl chloride, nothing happens....
View ArticleRobinson Annulation Mechanism
Mechanism of the Robinson Annulation. First, Michael Addition. Then, Aldol condensation.
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