Final, Just Reagents Flashcards
What would RX produce if combined with Li, Mg, or RONa?
RLi (with 2 Li)
ROR (with RONa)
RMgX (with Mg)
What general type of reactions does RX undergo? What are the usual partners?
SN1 (weaker nuc)
SN2 (strong nuc)
E2 (strong base)
What reactions do vicinal or geminal dihalides undergo?
Two E2 reactions with a strong base to form an alkyne
What reactions do MeX or EtX undergo?
Addition to =C: to form -CMe or -CEt
What general type of reaction can 3* alcohols undergo? What will they produce if combined with HX? Include stereochemistry.
E1 (strong acid)
Form RX (with HX), SN1 path
What general type of reactions can a 2* alcohol undergo and what kinds of products can it form when combined with HX? Include stereochemistry.
*Reduction questions on another flashcard
E1 (strong acid) Form RX (with HX), carbocation intermediate
What sort of things will a 2* alcohol be reduced to? What compounds will produce what products?
only ketones
Any of:
Na2Cr2O7 then H2SO4/H2O
KMnO4/OH-/heat then H+
PCC
DMSO/ClC(=O)C(=O)Cl then Et3N
What kind of compounds can be produced from a 1* alcohol reacting with a HX? Include stereochemistry.
*Reduction questions on another flashcard
Form RX (need HX)
inversion due to SN2
What sort of things will a 1* alcohol be reduced to? What compounds will produce what products?
Carboxylic Acids (Na2Cr2O7 then H2SO4/H2O or KMnO4/OH-/heat then H+)
Aldehydes (PCC or DMSO/ClC(=O)C(=O)Cl then Et3N)
What two compounds can be formed by any alcohol other than 3* when combined with PBr3 or SOCl2?
RBr (PBr3)
RCl (SOCl2)
How can alcohols be transformed into good intermediates (better leaving groups)?
Add TsCl or MsCl to make ROTs or ROMs
What will two identical alcohols and heat/light produce?
A symmetric ether
What special kinds of ethers can be formed by alcohols combining with 2-methypropene or ClSi(Me)3 ? What will they combine with?
Tert-butyl (RCH2OH, H2SO4 catalyst and 2-methyl-1-propene)
Silyl (all alcohols, base like Et3 or Pyridine, ClSi(Me)3)
What are the three ways an alkene can be turned into an alcohol? What would it need to react with and what preference do those mechanisms have for substitution? Include stereochemistry.
H+/H2O, carbocation intermediate
- Hg(OAc)2/THF/H2O + 2.NaBH4/OH- -> OH most sub, anti
- BH3/THF + 2.H2O2/NaOH -> OH least sub, syn + enantiomers
How can alkenes be transformed into compounds containing at least one X? What would they need to react with (3)? Include stereochemistry.
Alkyl Halide (HX), carbocation
Alkane Dihalide (X2 in CCl4), anti may produce enantiomers or meso
Alkane Halohydrin (X2 in H2O), anti with enaniomers
What are the two ways alkenes can be transformed into cis-1,2-diols? What would they need to combine with? Include stereochemistry.
Cold/Dilute KMnO4/OH- -> Cis-1,2-diols
OsO4 -> Cis-1,2-diols
either may produce enantiomers, depending on the starting alkene
What 2 sorts of cleavage can alkenes undergo? What would they need to react with? What sort of alkenes would produce what products?
+ Ht KMnO4/OH- + H+ -> Carboxylic Acid or Ketone or CO2/H2O by replacing the double bond with =O and replacing any hydrogens with -OH
O3 (then Me2S) -> Aldehyde or Ketone by replacing the double bond with =O
Describe the formation of epoxides from alkenes. Include stereochemistry.
The addition of a peracid (including mCPBA) will add an O across the double bond. May produce meso products or enantiomers.
Describe addition reactions of HX to alkynes. Include the effects of multiple equivalents and stereochemistry.
+1 HX -> RC(X)=CH
+2 HX -> RC(X)2-CH2R
H on less sub, X on most, anti addition
Describe addition reactions of X2 to alkynes. Include the effects of multiple equivalents and stereochemistry.
+1 X2 in CCl4 -> RC(X)=C(X)R
+2 X2 in CCl4 -> RC(X2)-C(X2)R
anti addition
Describe all 3 ways alkynes can be hydrogenated.
+ H2 with NiB2(P-2) -> Cis-Alkenes
+ H2 with Pd/CaCO3 (Lindlar)-> Cis-Alkene
+ Li/NH3 or Na/NH3 -> Trans-Alkene
+ H2 with Pd/Ni/Pt/Rh/Ru -> Alkane
What special kind of reactions can a terminal C on a triple bond undergo?
+ NaNH2 -> ☰C:
What special kind of reactions can a terminal CX on a double bond undergo?
+ NaNH2 -> ☰C (an E2)
What three kinds of reactions rely primarily on an acid? What kinds are used for each?
(hint: one general, one alkene, one epoxide)
E1 (strong)
Hydrogenation of Alkenes (dilute)
Opening of epoxides
What is Hg(OAc)2/THF/H2O then NaBH4/OH- used for? What kind of sterochemistry is involved?
Formation of alcohols from alkenes, anti addition of OH and H, OH most substituted side
What is BH3/THF then H2O2/NaOH used for? What kind of stereochemistry is involved?
Formation of alcohols from alkenes, syn addition of OH and H, OH least substituted side
What sort of things would X2 be used for under normal conditons? (react with alkene or alkyne)
React with alkene in CCl4 to form alkane dihalide (anti addition)
React with alkene in H2O to form alkane halohydrin (anti addition)
React with alkyne in CCl4 to form RC(X)=C(X)R (1eq) or RC(X2)-C(X2)R (2eq) (anti addition)
What would Br2 plus heat or light be used for?
Radical reaction with RH to produce RBr, most substituted products
What would Cl2 plus heat or light be used for?
Radical reaction with RH to produce RCl, all products
What are the three kinds of reactions that involve some form of KMnO4? (1,2 cleavage, oxidation)
Cold/Dilute with OH- + alkene = cis-1,2-diols
Hot with OH- and H+ in a second step + alkene = carboxylic acid, ketone, or CO2/H2O
Hot with OH- and H+ in a second step will oxidize 2* alcohol =ketone
Hot with OH- and H+ in a second step will oxidize 1* alcohol =carboxylic acid
What sort of things would OsO4 (osmium tetroxide) be used for?
formation of cis-1,2-diols from alkene
What sort of things would O3 + Me2S in a second step be used for?
formation of aldehydes and ketones from alkenes
What sort of things would NaNH2 be used for?
remove H from terminal alkyne to leave a lone pair
remove X from terminal alkene to form a triple bond
Describe the addition reactions of HX (2, alkene and alkyne)
To alkenes to form alkyl halides (carbocation intermediate, X on most substituted side)
To alkynes to form RC(X)=CHR, then RC(X)2-CHR (each time is anti addition with X on more substituted)
Describe the reactions of HX with various ethers: symmetric, unsymmetric where one side is 3*/benxylic/allylic, unsymmetric ethers (other types)
Symmetrical:
ROR + 1 HBr -(heat)-> HOR + RBr
ROR + 2 HBr -(heat)-> 2RBr + H2O
One side is tertiary/benzylic/allylic -> that side will grab the X in an SN1, if not it will go via SN2 (X the least substituted carbon on the opposite side, produce alcohol and inverted alkyl halide)
Describe the use of HBr in radical reactions with RCH=CH2. Include preferred conditions.
High temperatures and low concentrations.
Form RCH2CH2Br
What sort of things would NBS be used for? What would it be paired with (2)?
Production of Bromine Radials and Br2
(RCH=CH2)
Allyic Bromination of Alkenes with heat/light and ROOR
(+ RCH=CHCH3 -> RCH=CHCH2Br)
What sort of things would ROOR be used for? What might it be paired with?
Prompt Anti-Markovnikov reactions
Low concentrations of HBr, Heat
Promt Radical Reactions
NBS, HBr
What sort of things would PBr3 be used for?
Combine with alcohols (all except 3*) to replace OH with Br
What sort of things would SOCl2 be used for?
Combine with alcohols (all except 3*) to replace OH with Cl
What sort of things would TsCl or MsCl be used for?
React with alcohols to convert OH into a good leaving group (OTs or OMs)
What sort of things would ClSi(Me)3 be used for?
Formation of silyl ethers with alsohols and a base like Et3N or pyridine
Give some examples of peracids and describe what they are used for.
-CO3H or mCPBA are used for the formation of epoxides from alkenes
Describe the various types of ring opening an epoxide can undergo (3).
Ring opening with nucleophile, end up with base on less substituted side and OH on more, both anti
Ring opening with acid, end up with conjugate base on more substituted side and OH on least, both anti
Ring opening with grignard reagent (RMgX), end up with R on less substituted and OH on more, anti
What is NaBH4 (type of compound)? What will it produce when reacting with aldehydes or ketones?
Weak reducing agent
Reduce aldehydes to primary or methyl alcohols
Reduce ketones to secondary alcohols
What is LiAlH4 (type of compound)? What will it produce when reacting with aldehydes, ketones, carboxylic acids, esters, and alkyl halides?
Strong reducing agent
Reduce aldehydes to primary or methyl alcohols
Reduce ketones to secondary alcohols
Reduce carboxylic acids to primary alcohols (replace =O with two -H)
Reduce esters to alcohols (break bond from O to O, add H to each)
Reduce alkyl halides to alkanes (RH)
What sort of things would Na2Cr2O7 then H2SO4/H2O be used for (2)? (oxidizing agent)
Oxidize 1* alcohols to carboxylic acids
Oxidize 2* alcohols to ketones
What sort of things would PCC be used for (2)? (oxidizing agent)
Oxidize 1* alcohols to aldehydes
Oxidize 2* alcohols to ketones
What sort of things would DMSO/ClC(=O)C(=O)Cl then Et3N be used for (2)? What is this called? (oxidizing agent)
Oxidize 1* alcohols to aldehydes
Oxidize 2* alcohols to ketones
Swern oxidation
Describe RLi. What kind of reactions will it undergo (3)? (Terminal alkyne, water, synthesis)
Alkyl Lithium, an organometallic compound, R- and Li+
Remove terminal hydrogen from alkyne, leaving lone pairs
Produce RH from H2O (similar mechanism also applies to alcohols)
Synthesize deuterated/tritiated compounds when added to D2O or T2O
Describe RMgX, including its name. What kinds of reactions will it undergo (3)? (ignore production of alcohols, include alkyne, water, and epoxides)
Remove terminal hydrogen from alkyne, leaving lone pairs
Produce RH from H2O (similar mechanism also applies to alcohols)
Ring opening of epoxides, produce R on less substituted and OH on more, anti
Describe the four ways RMgX can produce alcohols. (hint: two main categories, ketone like or ester)
Break =O by adding -R to C and then add H to O- (will turn formaldehyde into primary alcohols, aldehydes into secondary alcohols, and ketones into tertiary alcohols)
Turn the =O from an ester into -OH, replace OR with two R groups from RMgX, (ester to tertiary alcohol)
