Ochem 1 Flashcards
(148 cards)
1
Q
Hydrazine
A
N2H4
2
Q
Vinyl
A
2
Q
Define observed rotation of a molecule
- What determines it?
A
degree to which a sample rotates PPL
- determined by:
- []
- length of tube, etc.
2
Q
Why are alcohols soluble in water?
A
They can H bond with water
3
Q
Cycloalkanes and ring strain
- How much ring strain do big, small, bicyclic & monocyclic cycloalkanes have?
A
- Cycloalkanes w/ LESS than 6 C’s have increasingly more ring strain
- Really BIG (10+) rings have enough freedom to approximate 109.5º
- BICYCLICring systems haveMOREring strain thanMONOcyclic rings
4
Q
If you see C6H5, what is it?
A
a BENZENE!
- not a straight chain
- since it has π bonds, it is unsaturated
4
Q
1º,2º,3º OH groups have 1,2, and 3 ___ ___ which do what to charge?
What does this mean?
A
Have 1,2, and 3 donating groups to destabilize charge
this is why 3º is less acidic than 1º
5
Q
Hückel’s Rule (for aromaticity)
to exhibit aromaticity
a ring must have EXACTLY __+__ electrons
A
to exhibit aromaticity
a ring must have EXACTLY: 4n+2π electrons
From what I’ve gathered, “n” is just 1 (at least it is for benzene…( 4(1) + 2π= 6 )
6
Q
Hemiketal
A
7
Q
Physical properties of alkanes
- Soluble/Insoluble in water?
- Low/High density?
- polar/non-polar?
- What increases BP?
- What decreases it?
- What increases MP?
A
- insoluble in water
- very low density
- non-polar
- BP increases with increasing chain length and/or MW
- BP decreases with increased branching (decreased symmetry)
- MP increases with increasing chain length and/or MW
7
Q
Cyclic rings create ___ ___ and make bond angles do what?
A
- ring strain
- make bond angles deviate from preferred 109.5º
7
Q
Alkenes are _____s!
Why?
A
Nucleophiles!
- π bonds are e’ dense and will attach E:philes
- forming a new bond to one of the C’s
- and leaving a CCI on the other
- CCI then attacked by a Nu:
8
Q
What does an SN2 rxn look like?
A
9
Q
Rank BOND REACTIVITY for:
- Single bonds
- Double bonds
- Triple bonds
A
triple>double>single
more reactive bc of π bonds
10
Q
3º ROHs can only be oxidized into ___?
A
PSYCHE!
They cant be oxidized at all!
11
Q
1º ROH can be oxidized into?
A
1º ROH⇒Aldehydes⇒Carboxylic Acids
12
Q
Alcohols are less/more acidic than water
- Rank alcohol acidity
A
LESS acidic than water
- ROH acidity increases from:
- (most acidic) 1>2>3 (least acidic)
13
Q
Imine
A
14
Q
Hybridization:
sp3, 1 LP
A
Trigonal Planar
15
Q
Hybridization:
sp3d, 2 LPs
A
T-shaped
16
Q
What is a racemic mixture a mixture OF?
A
50/50 mix of R and S enantiomers
17
Q
Anomers
- If anomeric OH/OR group and CH2OH group are on opposite sides of the ring, what kind of anomer is it?
A
ALPHA anomer
on the “Alpha-site side”
18
Q
Alcohols behave as either: ___s or as a ___
A
1) Nucleophiles
* (the lone pair on oxygen acts as a Lewis base)
2) Lewis acids
- ..when they are oxidized to carbonyl groups
- the oxygen ACCEPTS A PAIR OF ELECTRONS (Lewis Acid) from the O-H bond as the proton is abstracted
19
Q
Hybridization:
sp3d2, 1 LP
A
Square Pyramidal
20
Are **Alkyl** substituents **strong** or **weak** e' donating groups?
weak
21
Absolute conformation (\_\_ & \_\_)how do you **assign priority** to 4 R groups?
Assign priority starting with:
**HIGHEST MW**
(heavier=higher priority, i.e. 4)
(lighter, like H=lower priority, i.e.1)
If 1--\>3 is **clockwise=R**
If 1--\>3 is **counter clockwise =S**
22
**Gringard Synthesis**:
Describe the 2 steps (using **R-MgBr**)
1) Mg has **VERY LOW ELECTRONEGATIVITY**
## Footnote
* so the R group in R-MgBr **attacks** the electrophilic carbonyl C
* Occurs in **single** step
* kicking e's in C=O bond onto the **oxygen**
2) (-) charged oxygen is **protonated**
* yielding an **alcohol**
23
What are **diastereomers**?
**_Have same MF & connectivity_** (like steroisomers)
## Footnote
* are **NON**-identical, **NON**-superimposable*
* mirror images*
24
Amine
25
Anhydride
25
Benzyl
25
Sulfone
25
Hybridization:
## Footnote
***sp2, no LPs***
**Trigonal Planar**
Ex: BF3
25
HYbridization:
***sp3d, no LPs***
**Trigonal BIpyramidal**
Ex: PF5
25
Hybridization:
***sp3d, 3 LPs***
**Linear**
ex: XeF2
25
Rank bond **STABILITY** for:
## Footnote
* Single Bonds
* Double Bonds
* Triple Bonds
*Explain what **makes** the least stable one the least stable*
*single\>double\>triple*
## Footnote
* Triple bond is **LESS** stable because it has 2 reactive π bonds!
25
**RANKING** resonance structures
## Footnote
* You want **MORE** \_\_\_\_s, **LESS** \_\_\_\_\_
* The most **STABLE** species has the most *WHAT?*
*_**MORE** bonds, **LESS** charges_*
The *most stable species* has **the MOST POSSIBLE RESONANCE STRUCTURES**
26
Describe the **2-step** formation of:
## Footnote
* **TOSYLATES / MESYLATES**
1. **ROH** attacks **X** (via **SN2**)
* *kicks off X*
2. **H** is **abstracted** by **X** ion
*Mesylates and Tosylates are desirable because they make **very good LGs** that will react readily with almost **any** nucleophile*
27
# Define "**LEVORO**ROTARY"
* Using **FISCHER PROJECTIONS,** differentiate b/t **_D- Glyceraldehyde_** _and **L-Glyceraldehyde**_
compound rotates light
**_counter_-clockwise (-)**
28
Acetyl
28
2 molecules have the same **RELATIVE CONFIGURATION** if:
## Footnote
* Their **3D** arrangement is \_\_\_, but they have 1 (and **ONLY** 1) \_\_\_-\_\_\_\_ \_\_\_\_\_
_SAME **RELATIVE CONFIGURATION if:**_
Their 3D arrangement is **IDENTICAL**, but they have 1 (and **_ONLY_** 1) **_NON-IDENTICAL_ SUBSTITUENT**
29
Hybridization:
***sp3, no LPs***
**TETRAHEDRAL**
30
Structural/ **Constitutional Isomers** have the **SAME**\_\_\_\_, but different \_\_\_\_\_
Same **MF**
BUT
Different **connectivity**
32
**ETHERS**, **ROR'**, are excellent...?
**Solvents!**
33
**2º ROHs** can **ONLY** be oxidized into \_\_\_
## Footnote
*Can they be oxidized any **further**, like 1° ROHs?*
**Ketones**
*Can **NOT** be further oxidized*
34
What are the **2 types** of reactions you'll
see **ETHERS, ROR',** used in?
1. Ethers will almost **ALWAYS** be the **SOLVENT**
* *∴ wont participate in rxn*
2. If Ethers **DO** react, it'll only be **after** the **O- is protonated** by a strong acid (HCl)
* resulting in a **carbocation intermediate**
* which would then be **attacked** by a nucleophile
35
**Nitrile**
36
**Ester**
*HINT: Ester drinks **COOR**S*
37
What are a few common **OXIDIZING AGENTS?**
*HINT: **OKP**ee**P**ee!*
* **O3Cr2O7**
* **KMnO4**
* **PCC**
* **PDC**
38
List 4 characteristics of π bonds
1. prevent rotation
2. weaker than sigma bonds
3. less stable
4. more reactive
40
**Aldehyde**
41
_In **DEHYDRATION** of an ROH:_
## Footnote
* What is favored by a **HOT**, **concentrated** acid?
* What is favored by a **COLD**, **dilute** acid?
*In a dehydration reaction, what is the **MAJOR** product?*
**Alkene**
* is favored by a **hot, concentrated acid**
**Alcohol**
* is favored by a **cold, dilute acid**
***Major** product is the **more substituted***
*(more stable) **alkene***
42
Describe **SN2** rxns
Rate depends on **[] of 2** **species**
* so its **SECOND** order
* **ONE** step
_STEP_:
* **Backside** attack of Nu:
* w/ **simultaneous** ejection of LG
43
Carboxylic acid
**COOH**
44
**Alkyl** group
Hydrocarbons **ONLY!!!**
45
# Define a "**Base**" in an ochem reaction
* What do they do to protons?
* Are they electron dense or deficient?
* What kind of charge do they have?
**ABSTRACT** protons
* are **electron DENSE**
* have **full** or **partia**l (-) charge
46
Dehydration of ROH: synthesis of an \_\_\_.this is an ___ rxn
alkeneis an equilibrium rxn
47
What are Meso cpds?Why dont they have optical activity?Are they diastereomers? Why/Why not?
* -have 2+ chiral centers AND a plane of symmetry
* POS cancels out optical activity
* ARENT diastereomers, b/c diastereomers are PAIRS of cpds.
* Meso cpds are single cpds with a POS-
* Therefore, can't be diastereomers NOR enantiomers
48
# Define **"ALIPHATIC"**
* If something has a **benzene** ring, is it aliphatic or not?
Relating to organic compounds whose carbon atoms are linked in **open** chains
* either **straight** or **branched**
*_**rather** than containing a benzene ring_*
Something is either ****_ALIPH_**ATIC** or ****_AROM_**ATIC**
_Example_:
***Alkanes**, **alkenes**, and **alkynes** are aliphatic compounds*
49
**Enamine**
"**Enamine**" is derived from:
* the affix **en**-
* *used as the suffix of alkene*
* the root **amine**
50
_**Dehydration** of an ROH:_
## Footnote
* Describe the **3 steps**
* What **can** occur during this reaction?
* In what circumstance **would** it occur?
_Steps_:
1. **Protonation** of alcohol
2. Water (which is the **LG** here) **leaves**
* **CCI** is formed
3. **H2O** molecule **abstracts proton**
* ****e's **collapse**
* and form a **double bond**
*_**Methyl** or **hydride shifts** can occur_*
*if a **more substituted CCI** is available*
51
Ketal
51
Compare **boiling points**:
## Footnote
* cis vs trans isomers
**CIS \> trans**
## Footnote
* b/c of **dipole** moment, there are **increased IMFs** in CIS
* In TRANS, the dipoles **cancel**
* which means you'll have **less** IMF's
51
What is "**anti"** addition?
Where bonds are formed on **OPPOSITE** sides (of a metal catalyst, for example)
* Remember:*
* Syn=Gay (same sex/sides; is a **SIN**)*
* Anti=Hetero (opposite sex/ sides)*
52
List 4 characteristics of sigma bonds
1) DO allow rotation2) stronger than pi bonds3) more stable4) less reactive
53
What are **Enantiomers**?
What do they **need** to have in order to **qualify** as enantiomers?
**non-superimposable mirror images**
**of each other**
* Compound needs to have **at least 1 chiral center**
54
Substitution of **EPOXIDES** can occur via **what** **mechanism**?
*SN1 **_or_** SN2*
55
Describe **E2** reactions
Rate depends on [] of **two species**
so its a **SECOND** order, **one** step reaction
_STEP_:
1. **Abstraction of H+** leads to **double bond** formation
* ...while **simultaneously** ejecting LG
56
Hybridization:
## Footnote
**sp3, 2 LPs**
**Bent (V-shaped)**
Ex: H2O
57
What does it mean when two things are **"GEMINAL?"**
Both bonded to the *same* Carbon
| (are gemelos--twins)
58
Describe "**NUCLEOPHILES"**
## Footnote
* How do they react with atoms around them?
* Are electron dense/deficient?
* What's their **charge** like?
1. **Attack** **C's**
* or other **central** atoms
2. Are electron **DENSE**
* just like bases
3. Have a **full** or **partial** (-) charge
59
Ketone
60
Acetal
61
***Gringard Synthesis***
## Footnote
* What **is** it?
* What does it **result** in?
* What **3** **reactants** can it use?
* Production of an **ROH**
***...with an _EXTENSION_ (!!) of the C chain***
* Results in **increase** in the number of C's
* Can occur with the following reactants:
* **RMgBr** (Main one)
* *Electrophilic* **DOUBLE BONDS**
* **Cyano** groups
62
What is it that determines a molecule's **shape**
and bond **angle**(s)?
Its **Hybridization**
## Footnote
**sp vs sp2 vs sp3 etc.**
63
# Define "**Stereoisomers"**
list the 2 types
**Same** MF, **same** connectivity
*....but different **3D** arrangement*
_2 Types:_
* **Enantiomers** & **Diastereomers**
64
**Acyl** group
65
When an **alkene** is 1 C away from another **atom**, the ___ \_\_\_s are electron \_\_\_
the **π bonds** are e' **withdrawing**
67
Describe the **5 IUPAC rules** for naming a compound
1. Find the **LONGEST** **C chain**
2. The **terminal** C **closest** to a substituent is **#1**
* if it's a tie, one w/ **next closest** subst. is **#1**
3. Order groups **alphabetically**
* give # to **match** **C** to which it is **attached**
4. Dont forget **di, tri, tetra**, etc if **multiple** copies of the same R group are present
5. Put **hyphens** before **and** after R group #s
68
**Mesyl** group
69
**Hybridization** (there's **3** **possibilities** for this one) and **bond angle:**
sp3d2
**90º**
## Footnote
1. Octahedral
2. Square **pyramidal** (**1 LP**)
3. Square **planar** (**2 LP**)
70
**Amide**
71
Hybridization:
## Footnote
***sp2, 1 LP***
**Bent (V-shaped)**
Ex: SO2, O3
72
**_Alcohols_**:
## Footnote
* \_,\_,\_ **bonded to an H** can act as H-bond **donors**/ **acceptors**?
* What if they have LPs **NOT** attached to an H?
* **F,O,N** can act as **BOTH** an H bond donor **OR** acceptor
* F,O,N atoms w/ LPs that are **NOT** attached to a H
* ...can only act as H bond **acceptors**
73
sp hybridization
always linear (180º)
75
Dextrorotary
cpd rotates light clockwise (+)
76
Protection of Alcohols: what 2 things protect alcohols? What do they protect them from?what thing will remove a protecting group?
* TMS and MOM
* protect OH from oxidation (or related rxn) while at the same time letting the rxn proceed
* acidification will **remote EITHER protecting group** and **restore** ROH
77
Synthesis of an alkane
-reduce an alkene with H2 in presence of a metal catalyst (syn addition, remember?)
78
Anomers:if anomeric OH/OR group and CH2OH group are on the same side of the ring, what kind of anomer is it?
ß anomer
80
Vicinal
81
Physical properties of Ethers
* VERY non-reactive
* weakly polar
* ones with short R groups are slightly water soluble
* most non-polar species are soluble in ethers
* have low BP (no H bonding)
* **_Ethers are excellent SOLVENTS!_**
82
Formation of an RX from an ROH: -what mechanism is it?-what makes it unique?
* SN2 rxn
* SN2 are usually one step, **but alcohols need to get protonated first**
83
\_\_\_ ___ alkanes have the highest BP. Why?
-straight chain-always has higher MP than branched alkanes-among branched alkanes, increased branching=increased MP
84
Nucleophilicity is a function of \_\_\_\_?What does this mean?
-is a function of Kinetics-means it quantifies the rate at which a molecule reacts with an E:-describes how easily a molecule will react, but nothing about how stable the new bond will be
86
What are some common reducing agents?Reducing agents reduce a ___ to a \_\_
* NaBH4
* LiAlH4
* H2/pressure
...reduce a **carbonyl** to an **alcohol**
87
What is specific rotation of a sample?(hint: is ___ per\_\_\_, per\_\_\_)
* "is observed rotation per length, per concentration unit"
* divides observed rotation by length of tube and []
88
Why is cyclohexane more stable than cyclopropane?
Cyclopropane has tons of RING STRAIN!
89
Tosyl
90
NaBH4 can only reduce \_\_\_,\_\_\_ ONLY
aldehydes and ketones only
91
Ether nomenclature
* You can name each R group separately
* IUPAC wants you to name the LONGER of the 2 R groups as the "parent" chain, and the other R group as a substituent w/ "-oxy" suffix added
* ex: 1-ethoxyheptane
92
Which cyclic alkane is the most stable? How much ring strain does it have?
* cyclohexane
* has **0 ring strain**
93
Alkynes are nearly identical to \_\_\_s in \_\_\_?
nearly identical to alkenes in how they react
94
Remember the following about enantiomers (3)
1. they have R/S configurations at EVERY chiral center
2. They rotate PPL to the same degree, but in different directions
3. They have **identical** physical properties (BP, reactivity, etc) except for **how they rotate PPL** and the **products they form** when reacted with another **chiral** cpd
96
What does Valence Shell Electron Repulsion Theory predict?
* predicts shape molecules take due to the repulsion of the LP's of electrons
* ex: sp3 can be trigonal bipyramidal, seesaw, t-shaped, or linear depending on amount of LPs
97
Hybridization:
sp3d2, no LPs
98
What are E:'s?
* **e' poor** species with a full or partial (+) charge
* accept e's from either Nu:'s or bases
99
What is a polarimeter?
measures rotation of PPL as it passes through a sample
100
Hemiacetal
102
Epoxide
103
Basicity is a function of \_\_\_\_. What does this mean?
* of **Thermodynamics**
* basicity says nothing about how FAST a rxn will occur
* Only shows how much the molecule "wants" to react (how stable it is)
104
Alcohol MP properties
* increased MP with:
* increased Polarity and H-bonding
106
Describe SN1 rxns
* Rate depends on [] of one species, so its FIRST order-two steps
1. LG leaves, forms CCI (slow step)
2. Nu: attacks CCI (fast step)
107
Epoxides suffer from SEVERE what?What does this mean?
* Ring strain!
* This means they are **highly reactive**
109
Conformational Isomers
* AREN'T really isomers!
* when a molecule rotates around its bonds, these are "conformers," not isomers
* think about Newman projections, staggered & eclipsed, etc.
110
Nitro (FG)
111
Ether
112
Compare melting points: cis vs trans isomers
TRANS\>CIS
113
What are Epimers?What are a common example?
* A type of diastereomer
* differ are only 1 chiral center
* many **carbohydrates are epimers**
114
Epoxides are ___ \_\_\_ involving what?
cyclic ethers with 1 O and 2 Cs in a 3-membered ring
116
What should you know about Radicals? (2)
1. Its ***HETEROLYTIC ***cleavage sends **ONE e' to one species** and **ONE to the other**
2. can also form as damage to the molecule itself (radiation exposure)
118
Aryl
119
What is stronger, a sigma or a π bond?
sigma
120
Geometric Isomers: what are they when there's only 2 R groups attached? What about when there's more than 2?
2 groups: cis (same side), trans (opposite side)2+ groups: E (epposite side), Z (ze zame zide)(prioritize by MW)
121
Remember the following about cis & trans isomers (2)
1. Cis isomers often have dipole moments, but trans DONT (they cancel)
2. Cis isomers often experience steric hindrance, but trans DONT
122
Carbonyl
124
Hydroxyl
125
To be chiral, an atom has to be attached to...?What if it isn't?
* to 4 DIFFERENT R groups
* if it isnt, its not chiral
* therefore not an enantiomer
126
Hybridization:
sp3d2, 2 LPs
127
The Pinacol Rearrangement ("vicinal")-what does the rxn look like?-3 other details
* *vicinal diol*+hot acid--\>ketone or aldehyde
* the two OH groups must be in vicinal position and C's bearing them must be tri- or tetra- substituted by R groups
* if tri-substituted, yields an **aldehyde**
* if tetra-substituted, yields **ketone**
128
What are Leaving Groups?What are the "best" LGs?
* they leave the parent molecule during a rxn and take BOTH e's from the bond with them
* Best LG's are the **most stable after they leave**
* (ex: Halides)
129
Alkene stability
More R groups=more stable3\>2\>1
130
Alkoxy
131
sp3d bond angle and hybridization (4)
* 90º/120º or 180º (for linear)
1. trigonal bipyramidal
2. seesaw (1LP)
3. t-shaped (2LP)
4. linear (3LP)
132
sp3 bond angle and hybridization (3)
* 109.5º
1. tetrahedral
2. trigonal pyramidal (1LP)
3. bent (2LP)
133
What is plane polarized light?What is "optically active?"
* Light that exists in only a single plane
* "optically active"= DOES rotate PPL
134
How do you find the max # of (optically active) stereoisomers?
* =2n
* "n"=# of chiral centers
135
What catalyzes epoxide rxns, and how?
* Strong acids
* By **protonating O** and **making it a better LG**
136
Describe E1 rxns
1. Depends on [] of ONE species, so its **first order**
2. Two-steps:
1. LG leaves, forms CCI (slow step)
2. Proton abstraction leads to double bond formation (fast step)
137
sp2 hybridization (2) and bond angle
* 120º
1. trigonal planar
2. bent (1LP)
138
Alcohol BP properties
* increased BP with increased MW
* decreased BP with increased BP
139
**Combustion** of an alkane is a \_\_\_, \_\_\_thermic reaction with a ___ Ea
* **radical**, **exo**thermic rxn with a **High** Ea
140
What are Anomers?
* a type of diastereomer
* differ in 3D orientation **ONLY at the anomeric carbon** (1') of a ring structure
141
Hybridization:
sp3d, 1 LP
142
What are the 3 steps of a radical reaction?
1. initiation
2. propagation
3. termination
143
Which step of a radical rxn produces the most product?
propagation
144
***PEROXIDES***
***RO-OR***
145
***HYDROGEN PEROXIDE***
***H2O2***
146
Hückel's Rule (for aromaticity)
* Why is benzene **aromatic** and the 8-membered ring **NOT?**
**4n+2π**
## Footnote
* **"n"** is just any interger. But it needs to equal the amount of carbons!
* Benzene: here, "n"=1
* **4(1)+2π=6**
* For the 8 membered ring, neither n=1 **nor** n=2 works!
* You can't get 8 from **either** option
* therefore it **isnt** aromatic
