Reactions Flashcards
What is the stereochemistry outcome of using Na/NH3 on an alkyne?
Trans addition of 2 hydrogens across the double bond isolated at an alkene
What reagants are necessary to synthesize a ketone from a terminal alkyne?
What is the stereochemistry result of adding the following reagants to a terminal alkyne?
Results in a markovnikov addition.
(H2 goes to the least substituted Carbon, double bond O goes to the most substituted)
**If not terminal, will result in a mixture
What reagants are necessary to synthesize an aldehyde from a terminal alkyne? (anti-mark)
What reagants are used to form a TERMINAL alkyne from a vicinal or geminal dibromide?
What does an addition/eliminated reaction on a subsituted benzene require?
Leaving group to be ortho/para to the EWG
What is the result of adding the following reagants to a benzene with a suitable leaving group?
Formation of temporary benzyne transition state resulting in addition of NH2 to either side of triple bond.
When forming alkenes from vicinal dihalides using NAI or KI in acetone, what do we need to know about stereochemistry?
Wedges with wedges and dashes with dashes
(like E2)
trans-diaxial on cyclohexane
anti-coplanar on alkanes
What reagant is used to make a ketone from a carboxylic acid?
What reagant will allow you to form a ketone from a nitrile (R-C triple bond N)
R-Mg-Br
Grignard reagant
What reagant may be used to open an epoxide from the least substituted side?
Basic conditions are like SN2 (least substituted side)
What reagant would be good to use to build this ketone?
After the BuLi or PhLi step, add the R-X that you want to be part of the ketone.
What reagant must you add to this to get the R groups necessary to form an aldehyde or ketone?
What reagant will turn this into a dienophile? with 2 =O groups where the OH groups are?
Use of the acetylide ion with a primary or secondary halide results in what product and by what mechanism?
Because of the bulky halide group, reaction proceeds via the E2 mechanism. Results in the formation of a double bond after hydrogen is taken from acetylide ion and bromine leaves.
What is the result of the following?
What reagant allows you to substitute a hydroxyl group for a halogen on a benzene?
Use of the acetylide ion with a carbonyl group proceeds by what mechanism and yields what result?
The acetylide anion attacks the partially positive carbon.
Acidic water is then used to protonate the oxygen
What is the stereochemistry outcome of adding the following reagant across the double bond of an alkene?
Formation of a syn-diol
What two different reagant groups can be used to oxidize secondary alcohols (and yield the same results)?
What is the result o a Carboxylic Acid of adding 2 equivalent of R-Li followed by H30+ ?
The R group from R-Li is added to carboxylic acid
Also:
- B2H6/ diglyme
- H3O+
Boron reagant very selective towards carboxylic acids but wont reduce aldehydes or ketones.
Adding the following to a benzene results in what product?
What reagant will allow you to oxidize a benzene derivative to a single carboxylic group?
You can also use:
Na2Cr2O7/ H2S04/ heat
What reagants are necessary to add an N02 to a benzene?
HNO3/ H2S04
Result?
What is the result?
What reagant may be used to cleave a terminal alkyne and what are the resulting products?
(strong reagant)
What reagant may be used to cleave an ether?
HI or HBr (xs) and heat
** Need a strong acid
What is the result?
Cleavage of ethers by strong acids is done by what mechanism?
an SN2 mechanism
What reagants may be used in the formation of a dibromocarbene or a dichlorocarbene from an alkene?
What reagant allows you to turn a nitro group into an amino group on a benzene?
What reagants will temporarily create a benzyne and replace a leaving group with an NH2?
Wittig! C=C bond forming reaction
What is the stereochemistry result of adding MCPBA and CH2Cl2 to the double bond of an alkene in the formation of an epoxide?
Syn-addition and the retention of original stereochemistry
What is the stereochemistry outcome of adding the following reagants to the double bond of an alkene?
Formation of a syn diol
What is the result of the following?
What reagant allows you to add H and OH across a double bond?
(Anti-markovnikov and syn-addition)
What are the reagants necessary to add an S03 to a benzene?
What strong reagants are used to reduce carbonyls?
**reduces aldehydes, ketones, esters, acid halides, carboxylic acids (all carbonyls)!!
*uses ether as solvent
What reagant may be used in the formation of an alkyl halide from a tertiary alcohol?
What two reagant paths will allow you make an aldehyde from an acid chloride?
What is the stereochemistry outcome of using Lindlar’s catalyst on an alkyne?
Syn-addition of H-H that you can isolate at an alkene
What is the result of adding the following reagants?
** The aldehyde will not survive!
What reagants may be used to add H and Br across the triple bond of an alkyne to form an H-Br alkene?
(anti-markovnikov)
What reagant may be used on an alkyne to isolate an alkene with trans hydrogens added across the double bond?
With 1 equivalent of MCPBA and a molecule with multiple double bonds, which double bond will get the epoxide?
The electron rich pi bond because it reacts faster.
In an H-Br addition to a double bond at low temperature, what is the major product?
The major product is the product with the more stable transition state (lower Ea).
What reagants allow you to add H-X across the pi-bond of an alkene? (Markovnikov)
What reagant may be used to create a symmetrical ether from 2 equivalent alkanol groups?
What are the results of NaBH4 in a reaction with aldehydes, ketones, alkenes, acid anions, and esters?
What about LiAlH4?
Adding the following to a benzene results in what product?
What is the best method for forming an amido group from an acid chloride?
What must you add to this to get your ketone? (or in an alternate problem, the aldehyde)
What is the stereochemistry result of the following reagants?
Formation of an anti-diol
Because of the formation and opening of an epoxide
What reagant may be used to add a Bromine on either side of one of triple bond of an alkyne to form a dibromoalkene?
(only 1 equivalent used)
**Stereochemistry cannot be controlled
What is the result of adding the following to a benzene?
What reagant cleaves off alkyl groups from benzenes and turns them into carboxylic acids?
What is the result of adding the following reagant to a phenol?
Addition of H-X across a double bond in the presence of a peroxide, results in what stereochemistry?
Anti-markovnikov
What can be used to form an asymmetrical ether?
The Williamson Ether Synthesis
**Will not work on secondary or tertiary alkyl halides because of competition with E2
What is the result of adding the following to a ketone or aldehyde?
When choosing which N group to react with, remember that the two inner amido groups are resonance stabilized so won’t react as quickly.
What is the result?
What two different reagant paths can be taken to form a carbene from an alkene?
withdrawing groups are SP3 (3 looks like a W!)
What is the result of adding a grignard compound to the following reagants?
Formating of a carboxylic acid magnesium salt that is protonated by the hydronium ion.
What reagants can be used for the more HARSH cleavage of a double bond?
Note: involves oxidation and formaldehydes can not be isolated!
What is the result of adding the following to an acid chloride?
What reagant may be added to a terminal alkyne to form a ketone? (addition of H-OH to an alkyne)
What is the result of the following reaction?
Always a 1,4 diene
What reagant allows you to dehydrate an alkanol into a terminal alkene?
(giving the least substituted alkene)
This reagant leads to the formation of a terminal alkene
What is the stereochemistry result of adding the following reagants to an alkene?
Anti-markovnikov and syn-addition
What is the stereochemistry result of the formation of a dibromocarbene from the given reagants?
Results in a retention of original chemistry. (syn-addition)
What reagants are used to form an internal alkyne from a geminal or vicinal dibromide?
What reagant selectively reduces only carboxylic acids?
(But also reduces alkenes due to acting as a lewis acid)
What two different reagants will turn this into an aldehyde?
What is the result of this reaction?
No SN2 on SP2!!
What reagant will add an SO3H group to a benzene?
Fuming H2SO4
What reagants will reduce a ketone to a CH2?
In order to add an ether group to a benzene, what reagants are necessary?
What reagant allows you to add H and OCH3 across a double bond?
(Markovnikov and anti-addition)
What reagant allows you to add H and OH across a double bond without the possibility of rearrangement?
(Markovnikov and anti-addition)
What is the very temporary intermediate and result of the following reaction?
What two different reagant paths result in a syn-diol?
What is the difference between them?
Since you can’t go from carboxylic acids to aldehydes directly,
- SOCl2
- Rosenmund Reduction or mild lithium reagant
(LiAlH(otBu)3)
H2, Pd, BaSO4, S
Besides SOCl2, what reagant will convert a carboxylic acid into an acid chloride?
(more expensive, with better yield)
(COCl)2
What reagant can be used to turn OH into a better leaving group?
What reagant allows you to add H and OH across a double bond but gives a low yield and is often prone to rearrangement?
(markovnikov)
What reactant and reagant are necessary in the pinacol-pinacolone rearrangement?
What reagant reduces both carbonyl and alkene groups?
Raney-nickel reagant
What reagants will allow you to form an alkene from a vicinal dihalide?
What reagant may be used to reduce an alkyne all the way down to an alkene?
**generally bad yield
What reagant is used in the fischer esterification process?
H+
What reagants do you add to an alkyl halide to form a carboxylic acid?
What reagant is necessary to deprotonate a phenol?
Ethers in the presence of O2 (excess) slowly do what?
In an an H-Br addition to a double bond at high temperature, what is the major product?
At high temperature, the major product is the more stable product (more subsituted alkene). This is due to thermodynamic equilibrium and Le Chatelier’s principal.
What reagants may be used to form the alkoxide anion on primary/secondary alcohols? on secondary/tertiary alcohols?
What is the result of adding the following to a benzene derivative?
Strong oxidizer so cleaves all but the first carbon and the benzene.
What is the result of a grignard reagant reacting with an acid halide or ester?
Result is a product with at least two equal carbon groups.
In this example, the attacking carbon group looked much like the grignard reagant, hence why there are three equal groups.
What reagants allow you to add X-X across the pi bond of an alkene? (anti-addition)
What is the stereochemistry result of adding the following reagants to the double bond of an alkene for the formation of a carbene?
With syn-addition of the carbene, stereochemistry of the original alkene is preserved.
In order to add an alkyl group to a benzene, what reagants are necessary?
What is the result of adding an aqueous acid (H3O+) or aqueous base (OH/heat) to a nitrile (CN)
hydrolysis of nitrile reaction
What reagants allow you to add H and H across the double bond of an alkene?
(syn-addition)
What reagant may be used to form an aldehyde from a terminal alkyne?
What mild reagants are used for reduction of carbonyls?
**Reduces only aldehydes and ketones
What reagant will allow you to make a ketone from a nitrile?
What is the result of adding the following to a benzene?
Freidal- Crafts
What is the result of the following reaction?
Use of the acetylide ion with a methyl or primary halide proceeds by what mechanism and yields what product?
Proceeds by SN2, results in replacement of bromine with acetylide ion
What is the result of the fischer esterification process?
**The elements of water are lost from two compounds when they combine
What is the result from reaction between a grignard reagant and an epoxide?
Where does the grignard reagant attack?
This mechanism is SN2-like, the grignard reagant attacks the least substituted side
What reagants may be used to form primary and secondary alky halides from primary and secondary alcohols?
What reagants will add an aldehyde to a benzene?
In order to form a carboxyllic acid from a grignard reagant, what are the necessary reagants?
- CO2
- H3O+
What is the result of adding the following to a carbonyl carbon of an aldehyde or ketone?
Wolf-Kischner reaction.
When do weak and strong nucleophiles react with epoxides?
Weak nucleophiles only react with protonated epoxides
Strong nucleophiles only react with nonprotonated epoxides
What reagant allows you to dehydrate an alkanol into an alkene?
(to give most substituted alkene)
Works by an E1 like mechanism and can NOT give terminal alkene
What is the result of the following?
What reagant will turn a carboxylic acid into an aldehyde?
There are none! SOCl2 must be used to turn the carboxylic acid into an acid chloride which is more reactive.
What reagant will add an aldehyde to a benzene?
What is the rosenmund reduction?
What reagant may be used to form vicinal carbonyls from an alkyne?
The addition of the following to a benzene results in what?
What reagant may be used to form an epoxide from an alkene?
What reagants form the organolithium reagant?
What reagant will turn a phenol into an ester?
Fischer Esterification
What reagant may be used to open an epoxide from the more substituted side?
Acidic conditions open from more substituted side
Mixture of products due to benzyne
What reagants are necessary to halogenate a benzene?
- Cl2/ FeCl3
- Br2/ FeBr3
- I2/ CuCl2
What is the stereochemistry result of the oxymercuration/ demercuration reaction?
Results just like the acidic water reaction, except without the possibility of rearrangement and better yields.
Markovnikov and anti-addition
What is the result of adding the following to a carboxylic acid:
- LiOH
- R–Li
- H3O+
A ketone with the R group from R-Li.
Addition of a Halide across a double bond results in what stereochemistry?
Anti-addition
What is the reagant used to cleave vicinal diols (syn) into carbonyl compounds?
What reagant allows you to completely reduce a benzene?
What is the stereochemistry result of adding the following reagants to a terminal alkyne?
Anti-markovnikov addition
Results in the formation of an aldehyde.
(H2 goes to the more substituted carbon and the oxygen double bond goes to the least substituted carbon)
then H30+
Besides the potassium permanganate reagant used to cleave alkynes, what other reagants may be used that yield the same results?
What reagant will mildly turn this into a aldehyde?
The only alkyl halide that grignard reagant will react with is what kind of alkyl group?
An allyic carbon group because the electron density is delocalized.
What reagant allows you to add a CH3 directly to a benzene?
CH3I/ AlCl3
What reagant will reduce this?
What reagants may be used to add H and Br across the triple bond of an alkyne to form an H-Br alkene (1 equivalent) or an H-Br alkane (2 equivalents)
Markovnikov and syn-addition
What reagant may be used to form vicinal carbonyls on a terminal alkyne?
**Involves the further oxidation of H to form an alcohol group
What reagant can be used to oxidize a primary alcohol and form a formaldehyde?
Additon of H-X across a double bond results in what stereochemistry?
Markovnikov addition!
What reagants will convert this into a carboxylic acid anion?
What reagant may be used to cleave an alkyne? (strong)
What is the stereochemistry result of the addition of H2 and platinum (or another catalyst) to an alkene?
Results in the syn-addition of two hydrogens across the double bond
What Chapter 20 reagants were covered that can convert aldehydes to carboxylic acids (besides the already known ones)
What reagant allows you to generate a 1,4 diene from a benzene?
What reagants allow you to add H-Br across the pi-bond of an alkene? (anti-markovnikov)
What is the stereochemistry result of using HBr on an alkyne in the presense of a peroxide (1 equivalent)?
Yields an anti-markovnikov product and syn-addition of H and Br across the double bond.
What reagant is necessary to synthesize the acyl chloride from carboxyl group?
SOCl2
What reagant replaces the -OH group of a carboxylic acid with a methyl group?
- SN2
- great yield
What is the result of adding a secondary amine to a carbonyl aldehyde/ketone?
A secondary amine will result in an enamine group (C=C-N) rather than an imine!!!
**For more products, use H+ instead of H3O+
A halohydrin reaction on an alkene results in what stereochemistry?
Markovnikov and anti-addition
What is the stereochemistry outcome of adding HBr across the triple bond of an alkyne in the formation of either an alkene or alkane?
Results in a markovnikov and trans-alkene.
What reagants allow you to add X-OH across the pi-bond of an alkene (Markovnikov, anti-addition)
What reagant can be used to oxidize a primary alcohol to form a carboxylic acid?
**formaldehyde cannot be isolated, H further oxidizes into OH to form a carboxylic acid
What reagant may be used to form HS(CH2)3SH and a ketone with the given R groups?
What reagants can be used for the GENTLE cleavage of a double bond. What compound can you isolate from the final result?
Formaldehydes can be isolated from the final product.
Zn/acetic acid can be used instead of dimethylsulfide
What reagant may be used to isolate an alkene with syn-addition of H from an alkyne?
(Lindlar’s Catalyst)
What reagants are necessary to generate a 1,4 diene from a benzene?
What reagants will allow for the formation of an anti-diol across the double bond of an alkene?
**Involves the formation and opening of an epoxide
What reagants create the grignard reagant?
What is the result of the following? What’s important to note?
avoid using in the presence of alkenes, alkynes, alcohols, and amines.
What is the result of the following?
(Also KOH/DMSO as a reagant)
What reaction results in the formation of an acetylide anion?
In the below example, what Z’s are and are not allowed in the Friedel-Crafts reaction?
Remember: Z cannot be a deactivator (EWG) or an amine. Z can be an amido though!
What reagant will form a carboxylic acid from the following?
H2O
What is the result of adding the following to a carbonyl chloride?
Nucleophilic Acycl Substitution
What would you add to this if you want to get an anhydride?
What reagant will open the sulfur group and allow you to complete formation of the ketone or aldehyde?
H3O+/ HgCl2
Note: The 2 equivalent lithium reagant will continue to attack the acyl halide. Carbonyl chloride is very reactive!!
What reagant will strictly oxidize only the aldehyde?
Ag2O/ THF/ H2O
When you add an alcohol to an anhydridge, you open up the anhydride and add one O-R group.
**Remember that it reduces nitriles and amides.
What is the role of this reagant?
This reagant creates an alkyl halide with one less carbon.
If you want to turn this into CH3CH2CH2Br, what reagant do you use?
HgO/ heat/ CCl4/ Br2
or:
Pb(OAc)4 or Ag2O instead of HgO
In basic conditions, the carboxylic acid is deprotonated and the amine is neutral.
In acidic conditions, the carboxylic acid is neutral and the amine is positive.
What is the role of the following reagant?
DIBAH is a very mild reducing agent that can reduce esters (like the one below) to aldehydes.
What is the result of adding the following to an ester?
A transesterification to replace the R group from the ester with the R group in the reagant.
What is the result of the following?
** only works on primary amides.
What reagant will dehydrate a primary amide to a nitrile group?
**ONLY primary amides.
**Amido ONLY
What reagant will reduce an amido group to an amine?
**amido only because the OAlH3 group is a better leaving group than NH2
What is the result of adding Br2/ OH to the following?
** primary amides only
What reagant will decarboxylate an amide?
Br2/ OH
What reagant will turn this into a carboxylic acid?
Which amido reactions are only applicable to primary amidos?
POCl3 or SOCl2–> which turns amido into nitrile
Br2/ OH–> which eliminates C=O
**The LiAlH4 reaction that reduces C=O is applicable to all amidos but ONLY amidos.
What is the result of the following reacting with Br2 and Acetic Acid?
**Due to enol formation, remember that most stable intermediate (double bond) directs were the Br goes.
**This can’t be used for aldehydes because they oxidize to carboxylic acids and X2 is a mild oxidation agent.
What is the result of this?
Why?
Haloform reaction, final product is a deprotonated carboxylic acid.
This is due to the basic conditions in which a CX3 is formed and then leaves. (Carbon is a good leaving group in this case because of the halogens acting as EWGs).
What do the following reagants signal?
The Hell Volhard Zolinsky reaction.
Carboxylic acids can not be enolized easily so first converted to acid halides. Next is alpha bromination.
What reagant is used in the alpha-bromination of carboxylic acids?
What reagant allows for alpha substitution of ketones (not aldehydes)?
* Not aldehydes because they can be oxidized
What reagant allows you to alkylate ketones, esters, and nitriles (not aldehydes!)?
- LDA**
- R-Br
**LDA is a strong, bulky base that ensures enol formation. (shifts equilibrium)
What happens when you add this to –CN?
Remember, OH and H+ can act as bases and acids to turn a nitrile group into a deprotonated or protonated carboxylic acid!! Don’t be thrown off when it says NaOH
If a reactant grows by one or two carbons in length in a synthesis problem, what are very plausible possible reactions?
- Grignard attack on an epoxide. (Would add 2 carbons to length of chain).
- CO2 then H30+ to a grignard reagant. (Would add a single carbon in length.)
What reagant reduces this to an aldehyde?
What reagant turns this into a carboxylic acid?
Turns it into a deprotonated carboxylic acid which will allow it to react with carbonyl chloride to yield an ether.
?
How do you alkylate an aldehyde?
- Secondary amine
- R-Br
- H3O+
An enamine is formed and then the acid water removes the amine group after addition of the R to the double bond.
