Alcohols
What reagent can you use to oxidize a 3* ROH?
Trick question - there needs to be at least one H on the C bonded to OH group in order for there to be an oxidation reaction.
What metal is used to catalyze all cross-coupling reactions?
Pd - if on exam you forget the reagent at least write down "Pd-catalyst"
Reagents you should be familiar w/ is Stille(Sn), Negishi(Zn), Suzuki(B(OH)2), Heck(Alkene)
What gets attacked first in the Acidic conditions ? What do the intermediates look like? Now do the same for Basic conditions.
See solution on PPT.
Describe Fisher Esterification?
Foward: SM(s) --(reagent(s)) --> Ester
Fisher Esterification:
Carboxylic acid, ROH + Conc.H2SO4,Heat --> Ester
Draw/Describe the general Nucleophilic Acyl Subst. Rxn.
Carbonyl group-LG + Nu-H --> Intermediate --> Final
See PPT.
Describe the Difference between the Uses and reactivity of H2/Pt, NaBH4, and LiAlH4 in its reactivity with double/triple bonds, aldehydes/ketones, and carboxylic acids.
H2/Pt reduces everything, NABH can only reduce aldehydes and ketones, LAH can reduce aldehydes, Ketones and carboxylic acids. NOTE that after metal hydride step NEED acid/water workup step for neutral product.
How do you form a Ylide for the Wittig reaction?
Step 1: add triphenyl Phosphorous to an alkyl halide
Ph3P + RX --> Ph3P(+)--R
Step 2: Use a STRONG base (like RLi) to pull a H off of the C bonded to +P
Ph3P(+)--R + (-)C --> Ph3P(+)--(-)R+ HC
What are 4 Reagents to reduce carbonyl groups (aldehyde/ketone) to an ROH. (3 retains # of Cs, 1 adds Cs)
H2/Met Cat., NaBH4/CH3OH, 1.LiAlH4,2. H2O
then there are the organometallic reactions, ie.
1. R-Br, 2. Mg, THF, 3. H2O
Backwards:
Acid-Catalyzed Ester Hydrolysis:
Ester + (DILUTE acid) --> Carboxylic acid + ROH
Tie parallel to the foward and backwards of the ROH/ALkene elim dehydration/Hydration reactions
Basic Ester Hydrolysis - SAPONIFICATION (soaps!)
Ester + (DILUTE Base(NaOH,H20) --> Carboxylic acid + RO-
must add an acid workyp step.
Foward:
Fisher Esterification:
Carboxylic acid, ROH + Conc.H2SO4,Heat --> Ester
How can you use a grignard reagent to form a simple carboxylic acid?
R-MgBr + CO2 (1.THF, 2. H3O+) --> RCOOH
What reagents could I use to oxidize an ROH to an aldehyde or ketone? What reagents can I use to ox an ROH to a carboxylic acid?
ROH to Aldehyde/ketone --> PCC, PDC, Swern(1.dmso, 2.Et2N)
ROH to Carboxylix acid --> any of strong Cromium reagents (Jones, H2CrO4, etc)
Using these starting materials, write the general reaction and mechanism for the Wittig reaction:
- A R - ?
Ph3P(+)--(-):C + C==O --> ?
-B R* -
Reagent needed - DMSO and heat
products are (double bond forms btw C of carbonyl group and the -C of Ylide)
R - - A
= + Ph3P O
R* - -B
How is it possible to reduce a carbonyl group to an alkane group?
Wolff-Kishner(basic conditions) and Clemenson RXN(acidic) doesnt matter which you use.
What do you have to do to all Basic conditions once reaction has completed?
After a basic condition reaction the MOP will be the negative Ion, must add water to the solution in a separate step.
Which group (EDG or EWG) increase the acidity of the carboxylic acid?
EWG draw the electron density away from the OH bond, making that bend extremely weak and WAYYY easier to pull off the H, thus making that carboxylic acid a much better/stronger acid.
What is an example of a protecting group and when is it needed to use one?
a protecting group is using 2 ROH to protect the Carbonyl C of a carbonyl group. an example is HOCH2CH2OH w/ TsOH (classic sunglasses), to undo/ deprotect just add acid.
it is most obvious when you need a protecting group when you see that the carbonyl group is on both the starting material and in the final product if the reaction.
Primary Amines with an aldehyde/Ketone will form a what?
Imine
I only have access to Alkenes, but I need to form ONLY aldehydes/ketones? How can I do this in 1 step?
Ozonolysis! Specifically the Reducing agents - 1. O3,
2. Zn, H2O OR CH3SCH3
(or else any H on a potential aldehyde will be further oxidized to a carboxylic acid)
Describe the Hydrolysis of Nitiriles.
SM + Reagents --> MOP
20.16start with nitrile, add acid and becomes carboxylic acid
This is Prep of Nitriles(20.16)
(RCONH2)primary amide + P4O10, Heat --> RCN
Identify the general acidity/equilibrium arrow of the following :
Carboxylic Acid (H20) <--?--> Carboxylate Ion (H3O+)
Carboxylic Acid (H20) --> Carboxylate Ion (H3O+)
Equilibrium greatly favors the right side, carboxylic acid is an acid and is the most stable as its conj base, the carboxylate ion. This is also pushed in the foward reaction as both the Oxygens are able to have access to full (-) charge through resonance structures, and being the big e- greedy electroneg atom, both oxygens are very happy!
Acetal when an aldehyde is reacted with 2 ROH's that attack the carbonyl C(intermediate is a hemiacetal)
same goes for Ketal. (Ketone + 2ROH -> Hemiketal -> Ketal)
Secondary amines reacting with an aldehyde or ketone will form what? How do you know where the double bond will go?
Enamine - Bonus where will the doublebond go? On the side where it is easiest to take a B-H off.
Have an activated benzene? How can you add a carbonyl group to it? (Name of rxn and reagents needed)
Friedal-Crafts Acyclation (CH13) reagents: ClCOR, AlCl3
remember your Ortho, Para, Meta directing groups. This reaction only works well when you have EDG on the benzene!
Remake the Figure in the last page of notes: Replicate on white board - descirbe the meeting of this diagram.
(fn groups that should be included; Amide, Acid Anhydride, Acyl Chloride, Esters, Carboxylic Acid)
See PPT
Put in order of increasing reactivity of all the carboxylic acid derivatives; Amide, Acid Anhydride, Acyl Chloride, Esters
Most reactive to Least Reactive(i.e more stable)
Acyl Chloride>Acid anhydride> Ester> Amide